Seems like a presidential campaign being investigated and prosecuted because of a false conspiracy theory bought by his political opponents should be something a "principled" "liberty advocate" is concerned about, but he's been pretty mum on that. This has always been political- there's tons of exposure in antiTrump fanfare and he knows it.
That being said, his arguments about obstruction and impeachment are at least technically sound. I think impeaching Trump for his response to a phony conspiracy theory that haunted his administration and destroyed his political capital for 2 years, as opposed to blatant war crimes and corruption and collusion with other countries, is about as bogus as it gets. The pretenses of the investigation are so extraordinary and beyond the pale- compared to Trump's "obstruction" of an investigation that was given multiple years and unlimited resources to complete at great personal cost to his ability to conduct policy as the President of the United States, and Barr's "cover up" of a report that was released a few weeks later- that some response was warranted.
In other words, Trump had every right to be pissed off over the origins of the collusion investigations and feel like they cast an unfair cloud over his administration. As it turned out, there was no collusion, it was a complete myth, and his political associates were maligned as traitors to their country- for years!- based on a total fabrication. It was based on a lie. The notion that he obstructed the investigation into a fairy tale, while certainly relevant, is tiddlywinks by comparison.