[Tichy]

Maybe because you grow tired of silly arguments being repeated over and over again. I don't know much about climate science, but for example I think I know enough about evolution theory to be able to debunk the arguments of the creationists. Yet creationists won't give in - clearly reasoning is useless with them after a point. After a while I even suspect that the "opposing side" might have hired some people just to be obnoxious and bind the resources of "my side".

For example I felt it was sad when all new books by evolution researchers stared to be 50% arguing against the same old tired creationist arguments. I felt the energy would have been better spent advancing the science.