Unfortunately I've seen these kind of comments far too often both with people complaining about gaming or in discussions about LCDs vs CRTs etc. It seem a lot of people are dismissive with logic similar to this: "[the issue] does not affect me, hence anyone who complains must be...[insert favourite taunt]"
But if you consider that display technologies are imperfect plus how different individuals respond to lights, their sight etc., I am quite open to the idea that some people suffer from issues while others using the same equipment / playing the same game do not. Therefore I would not dismiss somebody's complaints of motion sickness, being able to see the sub-pixels on LCDs (TN I guess), those able to see the 6-bit to 8-bit trickery on LCDs, and so on. Just because I can't see something does not mean it does exist.
Personally in gaming the only issue I can recall is with Skyrim: the blurring and effects shaders in dungeons gives me a headache. I turned off most of them in the INI but I still get it a bit. What amazes me is that somebody obviously spent a fair bit of time and effort developing those shaders but aside from my issues with them giving me a headache, I think most of them (the blood one, the blurry lights) actually make the game look worse. Not to mention they make the game look more console'ly (bad IMHO).