Historically, reactionaries were those who opposed the French Revolution. Today, 'reactionary' is thrown around to describe anyone who doesn't agree with you.
It's human nature to react. It's a basic instinct for survival. The problem arises when dogma is made out of a reaction.
Some modern movements have acknowledged the reactionary nature of their ideology, such as neoreactionaries (as one would rightly guess). However, reactionary forces don't strictly belong to some traditionalist Right, opposing the spirit of revolution. You see a similar attitude on all fronts.
For some, fighting racists isn't good enough: they exhibit the same racist attitudes toward the one group whom they feel is oppressing them. Likewise, people who have bad experiences in church growing up become militant secularists. People who get attacked by their ultra-PC peers find comfort by following a few Alt-Right blogs and pretty soon, you hear them incessantly comparing the average IQ's of different races to make some point. Men who are tired of feminists start claiming that it is actually men who are oppressed.
What do they all have in common? They've found a community, and thus, for better or worse, a new party line.
The best thing to keep these communities thriving is a scapegoat: whether it's men, women, white people, black people, Jews, Rightists, Leftists, gays, heterosexuals or an aristocracy.
It's easier to find a scapegoat if the party in question can out-victim another group. The biggest victim wins cosmic sympathy and becomes, in this secular age, something akin to an inverted God; some version of Jesus with narrative emphasis on the degree of wounds rather than the level of innocence.
Most of this provides mere psychological restitution, more than anything. Each party calls the other 'fascist;' an indication that the conversation has ended.
We know how this ends, usually. The French Revolution's Reign of Terror and The Holocaust had something in common. Both of them saw some kind of solution in wiping out entire bloodlines.
Our next step forward, as a species, will have to happen without this enormous degree of scapegoating and its coextensive self-proclaimed victimization.
There will have to come a time when patriotism stops meaning arbitrary pride in something someone else did. We'll have to be personally responsible for who we help and harm. When that day comes, will we describe our position as 'auto-reactionary?' Perhaps we will reach such a stage of maturity that all wars and revolutions will become internalized.