When you see footage of something that clearly should not be visible based on what we believe, the argument provided is refraction, a mirage, or bending light. A coincidence that just so happens to match up to exactly what one should see, but no, it's just an illusion that makes it appear that way. Very convenient.
I have made certain observations myself. I don't have access to a boat though, but why exclude the hundreds of videos of people conducting exactly the experiments you describe, and just call them 'random videos online'? If I film and share something, it's just another 'random online video', too.
This is just one aspect though. There are many, many problems with the heliocentric model if you dive into the subject. Robert Sungenis is a geocentrist but not a flat earther. He has an documentary about this.
Fringe views are always ridiculed. I am comfortable with being wrong on this, the question is, are you?
Love Bitcoin? You're probably a far-right, transphobic racist. Everyone knows inflation is good for us and Bitcoin is a scam.
Antivaxxers were a joke to me just 4 years ago. Many woke up very fast once it became obvious that there was some validity to their stories. Of course there is a lot of bullshit mixed in there too.
I never bought the climate nonsense, but any dissent against this is treated the exact same way, even though many of us understand why it is fraud and not science.
Conclusions drawn via consensus should always be questioned.