The thing to remember about most Republicans (and Republican politicians especially) is that any arguments they throw out in pursuit of a particular goal only apply to that goal.

Impeachment of Trump was bad, so they said the Speaker didn’t have the power, that impeachment should be only for extreme situations, that high crimes and misdemeanors means you have to break the law to be impeached, that Democrats were on a mission to impeach Trump since he was elected.

But now, impeachment of Biden is good, so the Speaker clearly has the power to initiate an inquiry, that vague, shady insinuations with no hard evidence is sufficient to impeach, that they’re definitely not on a witch-hunt to impeach Biden despite investigating him from the moment they got their majority and moving forward to impeach with zero actual evidence.

You can point out their hypocrisy and they won’t defend themselves. Some of them might even try to convince you the situation is somehow different, but most don’t care. They set their sights on a goal and backfill an argument to justify it.