The great thing about reality is it is the final arbiter. To command it one must obey it.
Impersonally speaking, advocacy of truth and defending reality is not really necessary, because philosophies evolve and the right philosophy will catch on anyway, somewhere sometime in the universe. The only reason why we need proselytizing of truth is so as to improve the chances of individual survival. For example my survival would be unlikely in a society which thinks having a mobile phone means I am a devil worshiper who ought to be burnt at the stake. We all know such things happened in ancient times.
So when I wish, say, that a government shouldn't dictate what I eat, or the means of my voluntary association with others, I do it not out of some misguided sense of idealism, but pure greed to maximize my chances of survival. Systemically speaking it is not necessary. The system is much more stable than any theist or communist or post-modernist can fuck with. I just want to expedite the recognition of reality.