Not that long ago that was unheard of and either party could seat whoever they’d like in a committee. But similar to how the Democrats killed the executive appointment filibuster, they killed that as well by refusing to seat Republicans on the Jan 6th and removing some from other committees .
Now it’s going to come full circle. I wouldn’t be surprised if it eventually gets to unseating or refusing to seat a controversial figure.
Also,
> Both the House and the Senate make their own rules,
The rules for expelling congressmen are set in the US Constitution, they don't just make it up as they go. Unless you're talking about their ability to amend the US Constitution, but that's even less likely than kicking these guys out the normal way.
The best way to get them kicked out would be to have them convicted for bribery/corruption, then you might get a 2/3rds vote to expel them.