It is necessary to resist and struggle with someone you love over important issues, where it matters, and not simply cave in order to create peace. Peace, while important, is not so important it is worth caving over where important values will be sacrificed in the process. If you let someone you love do something stupid or counterproductive without even so much as a struggle, how much do you love them? It may sound "authoritarian" to speak of "letting" or "not letting" someone else do something, but sometimes you need to exercise the authority you do have, from within your power, to do good, and here it would be foolish to not do so, because people do not always make the wisest choices, and people often need to be strongly challenged to bring out their best -- or at least their better.
This is the lesson I've learned by listening to my mother in struggle with others. She often is right, and it often is taken as authoritarian by them, and that perception is just a cop-out if in fact -- as it most often is -- it is simply love in the form of tough-love. There are times where there is no point having any weight if you don't throw it around -- for good. The world has plenty of weight of its own, so if you don't throw in yours, how will you ever help tilt things in a good way? Should one behave as if one were weightless simply for a peace which in fact is capitulation of significant values?
There are times and places where love demands you hold your ground and stubbornly refuse to allow another to go against their best interests -- just as yes, there are times and places where you must let people make their own mistakes and learn from them. It's true that ultimately one has no strict control either way, but it is not respecting their agency if their decision is not tough enough to withstand serious scrutiny and dogged struggle : let them develop their agency in a tougher medium and come out with a more honed will.
It's not that we shouldn't be concerned about authoritarianism -- the imposition of will upon another that is arbitrary, ego-driven, and not in their broadest best interests -- we should. But will and the clash of wills is an important part of life, and we do not help people develop their agency if we surrender before their merest assertion. Let assertion be steeled in strong will and clash of wills, where it matters. And yes, where we throw our weight around, it damn well better matter, and we damn well better have scrupulously examined our own motivations to ensure their purity. And there is no point to strife for strife's sake, or giving others hell out of either pettiness or selfishness. But there is a place in genuine frith for strong, loving assertion of will.