I think it’s very simple. Will Hurd wants to run for something in the future, and thinks voting to impeach will make that impossible. Politics selects for the sort of people who find ways to reason to the position that will serve their interests.
Sometimes we look at congress and think about what a normal person would do. A normal person wouldn’t be in Congress.
Another thing is that moderate members are more partisan than people realize — partisan in the sense that membership in the political party is an important part of self-identity, aside from ideology or voting record.
Hurd voting to impeach would cause much trouble for his Republican house colleagues, and I suspect loyalty to them is a factor (at least unconsciously) that’s keeping even the least Trumpy Republicans from defecting.
