we live in a system that puts immoral people in power

Not just that, it pressures people to act immoral.

but I also don't have to make excuses for those immoral people acting immorally.

First of all, explaining isn't excusing. Second of all, one perversity of the system is that it makes everyone complicit by forcing everyone to participate, as consumers, participants in production, as participants in the political system, etc.. If you push that to it’s logical conclusion, everyone who isn’t committing their entire life towards overcoming the system can be blamed to act immoral, depending on how strict your morals are.

Putting too much focus on blaming people’s morals instead of focusing on the system that corrupts people’s morals is counter productive and creates a culture where people trying to do the right thing burn out and adopt an attitude of indifference because no matter how much you are trying to do the right thing, there are always more things to do. It also creates a culture where people compare and compete with eachother’s moral worth, which can lead to fracturing and infighting.

some of them do have a sense of shame

Shaming people into acting moral is not very effective imo.

There were plenty of things that she spoke out on

She sounds like a decent person, but my point is that if you look hard enough, you will find moral failings (same as with every human). I could blame her for not speaking out against Israel, for eample, and condemn her for it.

To be clear, I’m not in general against applying pressure on people in power by voicing disapproval or outrage where it is effective. What I find moderately annoying in this example is that people seem to focus more on Ed Sheran instead of focusing on the people with the actual power behind the decision to kick him (like Robert Kraft)..