Because many of them have long been compromised and not much better than the Democrats they pretend to stand against. Think about this, how can people making roughly $175k/year, in one of the most expensive areas of the U.S. while maintain a home in their voting district, become unusually wealthy?
Trump was a threat to them and their status quo. That status quo allowed money to flow into them through numerous channels: family members running companies that received government grants or gained foreign contracts, able to use money gained from election fundraising to pay a spouse or relative to "manage" their campaign funds, etc.
With Trump gone, they get to go back to the gravy train with a wink and a nod between themselves, and the occasional 'hearing' which acts as a kabuki theater for their constituents.
You are a voice of reason. Thank you for your comment.