PKK, specifically, has been influenced by soviet ideology, that much is true. But that isn’t reason to designate them a terrorist grp. The U.S. tends to designate non-nation-states as terrorists when they take up arms against a recognized nation-state to defend themselves, and when those nation-states request such a label to be assigned. Otherwise, mullahs in iran & erdogan’s turkey and SA should all be designated terrorist states based on their actions & often via terrorist proxies.
PKK is definitely a terrorist org. They have bombed civilian targets repeatedly.
I can sympathize with their goals while disagreeing strongly with their methods.