He may be a member of the Republican party but if you just look at his record as governor, you'd probably guess he's a Democrat. Pro choice, trans rights, thoroughly anti Trump, and even a lot of his tax cuts seem to prioritize relief for the working poor rather than the leech investor class.

Also, this is anecdotal but I've spent some time in Vermont and the conservatives there who I met were by and large reasonable, open-minded, and anti-Trump (there were a couple of exceptions but nowhere is perfect).

State politics are different from national politics. A blue state republican governor can sometimes be more left than a red state democratic governor.