I think part of it is that we're in the political equivalent of "total war" -- if a politician were seen as being friendly with political opponents they would probably be destroyed in primaries by party rivals using it as red meat for how they were "soft" or an "x in name only" or some similar idiocy.

See for example the criticism of Ellen's friendship with George W Bush.

Though interestingly the Obamas and Clintons don't get the same criticism for that, apart from occasionally being held up to suggest the centre left wing of the democrats isn't that different from the old bush-era republicans

Criticism of everything Obama related is next level compared to anything those others have had to deal with.

I’m not in the US and all of the names you listed have politics I disagree with.

As a counterpoint, a recently released via FOIA transcript of Obama to reporters in the last days of his presidency:

Obama: Privately, that's not -- [Trump's] interactions with me are very different than they are with the public, or, for that matter, interactions with Barack Obama, the distant figure. He's very polite to me, and has not stopped being so. I think where he sees a vulnerability he goes after it and he takes advantage of it.

A fair amount of it is still kayfabe to the pros (the problem is, it isn't to the public).

https://docs.google.com/viewerng/viewer?url=https://assets.b...