Reaction is about establishing order. A reactionary society is an ordered one, an ordered society is a conservative one. A disordered society is chaotic. Civilization is order, chaos is barbarism.
Regimentation is not necessarily order. A communist society is heavily regimented, but also chaotic. There is not order. Our growing anarcho-tyranny is heavily regimented, disordered, and chaotic all at once.
Natural order flows flow naturally from the relationships men are inclined towards. Regimentation is artificial, it is unnaturally forced upon society rather than flowing from it.
Regimentation may be necessary at times: a soldier in the army is artificially regimented as opposed to the naturally ordered warrior of a warband, but an army of soldiers is necessary for survival, as the warrior has been made obsolete (for now, 4G looks to be changing that).
Just because something is lined up nicely in a row or is heavily controlled does not mean it’s ordered. In fact, it is likely means it is regimented chaos. Chaos requires regimentation, order does not. In fact, order may look disorganized to the casual observer who doesn’t know better.
Regimentation is not order.