I mean, it's not like this idea is unfounded. Trump has praised Putin many times, including during the current invasion. Meanwhile, Putin has been very friendly towards Trump.
I think the "Russian election interference" stuff is very overblown, but it's pretty clear that Trump respects (and maybe even idolizes) Putin.
One other problem with what you said is that I think the cause and effect goes the other way. The democrats are anti-Trump in part because he's pro Putin. They're not anti-Putin because Putin is pro-Trump. Being anti-Putin is very simply a matter of being anti-dictator and doesn't require tying Putin to a controversial US political figure.