There can't be evidence that it's completely safe, although I would agree with you on both counts, I use Bluetooth as well.
The point of the original article is - if you believe it's a problem, don't be irrational to prefer much stronger signals just because you are worried about the little antennas. Antenna closer to you makes your phone broadcast much less. Prefer wifi mesh over a single access point (phone has to transmit only to closest ap, not through the walls - and all modern phones adjust transmit power). And prefer wifi to mobile, there's an order of magnitude difference in power.
And transmitter you hold in your hand is much more important (n^2 of distance) than the far transmitter of access point.