> although [Didi drivers are] obviously careful not to go too far for their own good
I don't think any Westerner seriously feels that they could be jailed for anything short of telling some official that they're going to kill the president or some major leader. Person to person, you can say whatever. As much as I don't like the NSA's overreach I don't think they are listening or don't bother themselves with these acts (one of the two has to be true given the last decade).
So I'd say that's one big difference.
You're also talking about a time when America has record distaste and distrust for their politicians and president. It wasn't always like this and I think your argument would be fine if the majority of people supported the state, but that's just currently not the case.
> You reap the benefits of all these policies you are supposedly against
How do I not? Seriously. I didn't choose to be born in this country. I can't just not reap the benefits. There is no method for me to pick and choose my benefits based on my personal beliefs. So I'm not sure what you expect me to do. There's no country I can move to that is doing significantly better. The only action I can see is to attempt to change what is happening here. But if you see more that I can do I would appreciate the advice (I'm serious). I'm not resigning to my "fate". A defeatist attitude is a step backwards.
> Is this really any different from a Chinese police officer saying “I was just following orders”?
Yes. I'm not sure why you think the populous is the same as state actors (police). They are different entities. Also, "just following orders" isn't an excuse in the military, let alone international law. It doesn't hold up here in America. You can go to jail for committing crimes that you were ordered to commit. Doesn't matter if you're the head of the military following the president's orders (you may notice that generals do ignore presidential orders, see the Muller report) or a police officer following the chief. Authorization does not protect you in a court of law.