There are many good reasons to oppose the state, but for me, the most compelling (and most fundamental) is my belief in liberty. Liberty first. Liberty above all else. My belief in liberty does not end with advocating the abolition of the state, however; I likewise advocate the realization that all claimed authority over anyone but oneself is illegitimate.
Attempting to control other people is evil. It’s a violation of their fundamental right to liberty. It doesn’t matter if the entity or individual attempting to exercise the control is a state, a church, a parent, a teacher, or a president. No one ever has the right to exercise control over anyone but themselves. Stop trying to control people! Let them make their own decisions about how to think, speak, dress, act, travel, experiment, build, create, love, hate, celebrate, protest, play, work, and do anything else they might wish (short of actually initiating violence against others, of course) without interference.
Liberty isn’t just about freedom from the state; it’s about freedom from all external control.