Whatever you want to call it. Personally I'm using the mechanism to indicate agreement with a particular argument or point, but I don't see why you or anyone else couldn't use it for whatever other reason you want. Of course, that's using the heinous assumptions of individualized expression rather than social conformity.
You seriously can't imagine any other reason to register and participate on a forum thread than the desire to be taught a particular social conformity by the people who happened to already have been on that forum?
I wasn't aware of places one could argue with the new organizers of the bookfair such that they didn't directly control the blocking & deletion mechanism. Clearly, if such a place were available and known to me (one still isn't, you haven't actually pointed at one) then it would have been preferable if it indeed also allowed individualized expression.
When we were teenagers a friend of mine was with the Jehovah's witnesses for a while, and one time I went along to one of their meetings to check it out. There was this guy delivering a lecture about how General Relativity proved that God exists using the usual crackpot stuff. When I pointed this out after the lecture to my friend and a couple of people I was surprised to find out that they defended it on the grounds that it gave them some sort of community feeling. Serious question though: Is responsibility one of those community values? Because it seems, to me, that going around making crackpot claims while hiding behind transgender people could be considered highly irresponsible. You know, for the flak it will obviously generate.