The problem with this approach is, that while you complain about or criticize made decisions, you are not offering alternatives. So as long as we do not see a better alternative, what are we supposed to do? Complaining is very OK and an important part of debate, but without providing a better way to act, I do not see how one can expect complains to change anything.
Doing "nothing" is also an alternative, but here it comes into play, what kind of person dictates the aggressor's forces and what is known about them. If, merely hypothetically speaking, of course, the wanted to establish an empire under their rule, without regard for what others within that future empire want, what makes you think, that it will stop with that one country the aggressor is invading currently? Especially when history has proven, that further escalation is on the menu a few years later.
I think the "doing nothing" or an appeasement strategy is quickly reduced to absurdity, if we look at the past and think about what would happen in the future. In fact, some people have warned about what is happening right now, at least since 2014.
We have the choice to condition the dictator further, by giving in to every future demand, because he will learn he only needs to threaten with nuclear weapons (and he _will_ find a "reason" to be insulted, or simply make one himself, with lets say some false flag operations for example), or say no to that. We have made the mistake, of allowing this to go on for far too many years already, so that he felt too sure, that it would work this time as well. Good, that we put a stop to that. Maybe, if we had done so earlier, we would not be in this situation right now.