How much power does and ATC Controller possess?

[Calvin Waterbury]

...
If you are rejected, or told unable due to a reason, I wouldn't bicker on the frequency. Either continue the flight as per your training or do not fly at all. Then, when you have an opportunity, call the facility and engage in an educational and constructive conversation where you can learn more about the situation.
...

[Emphasis mine]

Solid gold! Double thumbs up!

[Peter Grey]

I was later merged into the arrival stream while doing 160-180kias, the same speeds they were being reduced to.

I hit 180 going into ATL today.... on a 4 mile final.

More on point, generally atc wont assign a "wrong star", but they can if needed. Once when going into sna in something a bit slower than a crj I was assigned the kayoh arrival which has a 180kt restriction. The plane couldnt do it so I told atc unable and they just deleted the restriction for me.

When we got closer to that fix socal vectored us out of the way and problem solved.

So to summarize, work with atc and we will work with you.