I don't think I've mentioned word pseudoscience.
The article you presented is factually incorrect. There is a very easy way too ensure that LEDs don't flicker: feed them a steady DC current. For example, if you have a regular AA battery and an LED of the appropriate design, you can simply connect the legs of the LED directly to the battery and you'll have a steady, flicker free light until the battery dies.
The issue you bring up and that you don't seem to understand is that rectifying AC to DC often doesn't leave a smooth level of current moving through a circuit. If you string enough individual LED chips together, you can simply wire the LEDs into am AC current circuit and you'll get light, but, it will obviously flicker at the cyclic rate that is being fed to them. In the US, this is 60Hz, and most of the rest of the world that is 50Hz. In fact, many newer, cheaper, simpler LED lightbulbs do this, especially the "filament style" bulbs. There are some drawbacks to this design: if the voltage goes out of range (either from a brownout or a voltage spike), the chips can let out the magic smoke, so these tend to not be as reliable as bulbs that are fed steady DC or have a good AC rectification circuit.
That brings us to the subject of AC rectification. This is a fairly huge topic, as nearly every piece of electronic equipment today is, as some point, powered from an AC system. So, unless you are going through the trouble of running your whole life on strictly DC that you generate via atypical means, plus you have no exposure to WiFi, radio waves, sunlight, infrared, etc., you are being exposed to oscillating waves of all sorts. To state for the record, I do think that various frequencies applied in specific ways are, in fact, intentionally being used to manipulate and directly harm us humans. That's out of the scope of this discussion. I will be limiting my part of this discussion to hopefully helping you understand why I think you're too worried about the flicker and also helping you understand that it can and is easily eliminated at the point of use, which is why (again, putting aside the spectrum emitted) LEDs CAN be perfectly safe, and in many cases preferable to incandescent lighting.
For the sake of this discussion, let's put aside cheap, junky stuff. Ok? Cheap LED lighting systems are very likely problematic in that they likely do emit unwanted EMF from the power supplies that rectify AC to DC to power the LEDs. Eliminating the cheapest, awfullest stuff, we are left with quality electronics.
If what the author of that article is saying is correct, that would mean that absolutely NONE of your electronics that use would be reliable. None. Point blank. Full stop. Period. Anything with any sort of processor would die nearly instantly if the processor did not get steady, clean DC power. Since this is case, that means that power supplies that can take the AC power from the grid and rectify it to steady, clean DC power not only exist, but they are so common these days no one gives them a second thought. Any appliance that isn't just a very simple physically switched motor needs DC to function, and this has been known stove the very beginning of electrification. (I'm sure you are aware of the AC vs. DC war between Tesla and Edison.) The means to rectify AC to DC and then invert DC to DC has been known for obey a century at this point, though we do now have more compact and much more efficient means to accomplish both conversions.
The most common DC power supply these days is a switch mode topology. You can read up on how those work if you like, as I don't exactly want to type that out here since I'm on my phone and enjoying a fire in the wood stove. My point in bringing these up, though, is that they are capable of producing very stable DC given a bewilderingly wide set of inputs. (Anything that can operate "worldwide," as an example.) Now... If the author of the article can't source, design, or build a DC power supply that can handle normal grid variation to supply a VERY simple load (driving an LED is nearly as simple as a resistive load), then I will say that he is ignorant or incompetent. Saying it is impossible to prevent flicker of an LED lighting element is just daft. I can say this because *I* have managed it just hacking at circuit design with some of the cheapest parts I can source on Amazon and a few electronics suppliers. If I can manage that, an EE (or someone who takes electronicsas a hobby much more seriously than I) should be able to do it better, cheaper, and simpler than I can.
So... To sum up: good LED light sources do not flicker. At all. By any definition. Granted, a good light source won't be cheap. I know you're not into cheap since you have shown a propensity to quality that is admirable. But... I just don't think you've got a clue about the underlying tech in this stuff.
Now I'd like to bring up another aspect of this whole complex topic: dimming and PWM for other purposes.
Most LED lighting systems that are dimmable use Pulse Width Modulation to achieve a lower light output. This is a cheap and easy way to do so. The power supply emits pulses of current of various durations with a pause in between. This is not "flicker." This is an intentionally induced method of controlling the light output and also can be used to save power and lower heat generation in a lighting system.
This is also where things can get hinky. Certain frequencies of pulses can trigger epileptic fits. That's very well known at this point. However, it is my speculation that doing this at certain frequencies is capable of subconsciously manipulating humans in various ways, though I'm not at all capable of providing too much proof of that at this time. If you'll at least follow along for a bit, then we can at least have a discussion about this as a possible source of causing harm to humans.
If what I'm saying is true, that certain patterns of lighting can be harmful to humans natural rhythms, then, yes, LED lighting can be considered harmful and should be avoided, though that is nearly impossible these days if you come into contact with any "civilization." Store lighting is almost assuredly LED. Any vehicle on the road with LED headlights is absolutely using PWM driving of the headlights. (I find some engineering choices of what frequency to use to drive the headlights superlatively annoying, even if I understand some of why they choose the methods they do.)
As the saying goes, "dosage makes the poison."
How much of what kind of what color at what time is bad for us? I cannot tell you. It is not all bad. Nor is it all good. But I will state that I prefer nearly ANY LED lighting over awful fluorescent bulbs. I'm very glad those are nearly all phased out in most places I've come across.
Anyway... Just saying "LED bad" is daft. It is not all bad. You just have to be selective, just like with everything else.
