Acceptance of all that exists in the current moment, for me, doesn't mean apathy but stopping to avoid uncomfortable aspects of reality. The difference is between accepting what is so and thinking that's the way it's always going to be. Facing reality can be a strong motivator for change.

I think the idea is more similar to "accept you have a drinking problem." It isn't that you should embrace bad things, but that you should get rid of your mental aversion so you can respond consciously rather than instinctively. It might mean that you react less aggressively than you would have if you realize it's not really a battle you want to fight. It might also mean you respond more proactively if you realize you were ignoring a problem (as with alcohol abuse).

In practice, Buddhists do protest, but they tend to stop before the point where things turn violent (at least from my reading of history). As for why the people in that country put up with the dictatorship: A lot of people, regardless of faith, but up with bad governments for a long time. As a counterexample, though, IIRC monks in Burma were among the most vocal opponents of the junta.

Theoretically, the goal is simply to avoid the knee jerk reaction. Accept the reality as what it is, then figure out what you want to (and can) do about it - rather than succumb to your animal instincts.

As for why these Buddhists put up with the dictatorship, you'd have to ask them... Keep in mind different people interpret Buddhism (and meditation) very differently.

Personally I interpret a large part of acceptance as stopping the endless stream of "what-if?"'s and doubt and stress and fear surrounding what happens in our lives.

When faced with an event, ruminating endlessly about what might have been if you did X instead of Y, or worrying about what might come next stops you from actually being free to focus your attention where you want it: On what deliberate action you should be taking, and on enjoying the good things in your life.

And that might have the effect of inaction in many cases. For "common people in that country" you mentioned it might very well be that on consideration an uprising was far down the list of what actually mattered to their lives. I don't know what impact it had on their day to day lives, and how that measures up with other things, such as caring for their families and making a decent living. Or maybe "acceptance" had nothing to do with it and they were just scared.

But priorities shift once you take a more deliberate view and are not driven by anguish about a situation but about considering carefully what actually matters to you.

A simple example:

You look at the clock, and realize you're late. There's no way you can make it to where you were meant to be in time.

You can choose to get stressed out and frantic, but it's already too late - you won't change that, all you achieve is to be stressed out and frantic and running around like a headless chicken while life passes you by.

Does it matter if you're late?

Maybe it does, but it still doesn't help to stress out about it when you should instead focus on what the best course of action is. Perhaps it is as simple as a phone call to let someone know you will be late. Perhaps you miss a train, but can just take a later one. Why stress over it? Even if being late is a disaster, the stress achieves nothing. It is unhelpful and just makes things worse. So you accept that you will be late and take deliberate action to minimize the impact of being late, and you accept the consequences you can't mitigate rather than make things worse by feeling sorry for yourself.

Maybe it doesn't matter, and you should just breathe calmly and accept that you will be late and since it's not such a big deal you proceed as you otherwise would and enjoy your walk wherever you were headed and take in the view and enjoy the nice day. Maybe you won't look at the clock in the first place, because you know it does not really matter what time it is.

Most things people get terribly worked up over are never worth caring much about in the first place, yet we get worked up and stressed out and make stupid mistakes or feel miserable for no good reason. Focus your attention and energy on the things that are worth caring about, and even then try to make a clear distinction between deliberate action and feelings or actions that are not helpful.