Usually people you describe are very unwell and suffer from something they aren’t addressing through proper channels like professional help/ therapy or just not willing/capable to fix their own life.

They usually are angry about things going wrong in their own life, don’t know how to address it and how to fix it, so they lash on to others. They lash passive aggressively and not directly because it’s easier. Honestly I feel sad for them. Their life is a mess.

Whenever possible either tell them directly to back off or ignore them. Not worth your time. Unless you must interact with them (like at work) don’t waste 5 minutes on them. If they ask for help, advice some way of improving their lives. And if not, let them ride into the sunset. We all have bigger fish to fry. No time to deal with silliness