The explanation isn't for why people care about politics per se, but that we care so deeply for politics that we respond to adversity much, much harsher in political environments than in others. Or, our reactions are disproportionate to the actual risks involved in it. People become angry when discussing if something should be privatized or if taxes should be raised. If one believes that there is some general policies that most benefit from, it's really bad to become angry at those whom you really should be allies with.

I feel like many people (especially the type of people who discuss politics) have strong political opinions that aren't rationally justified. When their beliefs are attacked they get emotional because they can't back it up with logic.