Should Flat-Earthers be debated or ignored?

[Anomalocaris]

How level was the camera. the reference lines are drawn in and that could easily be on the slant.

I'm curious to know why you present this as a possible objection. It seems that to make the objection you must first agree with the man's assumption that we should see a drop in height; you account for its absence by a possibly slanted camera. If it turns out the camera was level, what does that do for your position? Will you come up with another objection; or accept the man's point?

Why would Anyone present that as possible explanation?

Because that is how science is done?

Because the most important thing required to do science is not skill in thinking you had discovered new things, but instead it is the skill in discovering why what you think is new is not new at all?   

The practice of science requires you to exclude all possibilities that your enthusiasm Had told you were a new discovery were in fact nothing of the sort?

Only when you’ve exercise your full measure of skills in discovering why what you think you discovered, you in fact didn’t, are you even beginning to enter the place where you can seriously consider the possibility that what seemed to be new during your moment of exuberance could in fact be new?

Let’s just say the purported evidence is so trivial, that had it actually been as the man described it, it would have been found a long time ago by people far more observant and less gullible than he, much less you. 

You seem to think the weight of accumulated evidence doesn’t matter.   Fruit of vast human endeavors are so flimsy that people of modest intellect, trivial education, high self esteem and low capacity for critical thinking would readily overturn it with what can be gleamed by one single glance.