The issue with sceptimatic isn't his opinions, it's that his posts are low-content. All he has to say on every subject just boils down to something along the lines of "That doesn't seem right to me." And that's it. Say what you like about odd theories that have been debated before on this forum, like dinosaurs building boats, moonlight being dangerous, or alternative histories of the world, but at least there was something to actually discuss with those topics. Their proponents put in genuine effort to make arguments, support their claims with evidence, logically rebut objections, etc.
With sceptimatic, however, the only thing that's relevant is sceptimatic. At the end of the day, he just doesn't like something and so determines that it's wrong. We can't debate that. There is no discussion to be had on sceptimatic's own little reality where he personally decides what is right and what is wrong.