One of my least favorite liberal tics is to grant there was some time when American conservatism was some sort wrong but noble affair, and to appeal to various horrible things as some deviation from those principled norms. The American conservative movement (which while not identical to the Republican party, it has been latched onto its face planting its eggs in its body Alien-style for decades) has carried the banner of white nationalism, bigotry, contempt for the poor, corporate immunity, environmental destruction, rigid unequal gender roles, homophobia, xenophobia, "law and order" policing, state discrimination, the military state, perpetual global war, support for worldwide dictators, American "empire" in its various manifestation, etc. That isn't to say all Republicans (or even conservatives) have been that bad, or that team D has been pure(certainly not!), but these are all things which are deeply in the DNA of the conservative movement. I mean, ok, Teddy Roosevelt started the national park system, but I don't think your appeals to "conservatism used to be about conservation!!!" are really going to win any converts.
Liberals imagine they catch conservatives in some violation of their own supposed principles all the time. This is only proof that conservatives have successfully conned a lot of liberals. They haven't conned themselves.