For the longest time, “liberal” seemed like it basically just meant “Democrat” the same way “conservative” has/had been used to mean “Republican.” Now, it seems like it means “bad Democrat” and is even worse than being MAGA the way many seem to use it. Where did its use as an insult within the [relative] political left come from, and what does it specifically accuse/identify someone of/as?
Using liberal as a derogatory says far more about the person saying it, than it does about those they say it about.
My advice is to not take them seriously.
^ perfect answer, IMO.