When something is infected and spreads nasties, you need to isolate it from the healthy population.
Be it a plant harbouring spider mites, negativity, idiotism, STDs, criminal activity, or the stomach flu, that shit needs to be put into quarantine until the individual gets better and can be released back into the wild. If they don’t get better, they will have to be discarded.
Let that be the life lesson of the day. No, for the whole life.