When someone just won’t leave you alone, especially someone who has said inappropriate things previously (in this case, AT WORK), it’s legitimately threatening. It ruins the party at best, and it makes you fearful for what might happen afterwards. “Insidious” is 100% the correct word. It instills dread.

I dismiss pretty much anyone’s opinion as soon as I see the use of “PC”. I no longer have any interest in what that person has to say because it indicates to me that they care less about actual human beings than about not being able to say whatever they want without criticism.