Quite a lot of those Senators are well trained lawyers and know this. Cruz in particular has an amazing legal background. Lindsey Graham led the impeachment of Clinton.
AIUI once you pass the bar, you are a lawyer unless disbarred. But being disbarred has select criteria that need to be proven. I'm not sure what those are. But I'm pretty sure that "being a dick" isn't enough. Simply because there would be no professionals left.
Quite a lot of those Senators are well trained lawyers and know this. Cruz in particular has an amazing legal background. Lindsey Graham led the impeachment of Clinton.
They know better. Which makes it worse.