I do look before blocking someone. If I think they are just having an off-day I don't block them but if I see that they are consistently being nasty and trying to upset people then I block them. Sadly, they do seem to need help but we also have to take care of our own mental health & wellbeing.

We do. I have been a little bewildered at times by some remarks but you can't really rationalise about it, be they spontaneous outbursts or more malignant tendencies. We all have our off days or sensitive topics so being occasionally vitriolic about something strongly felt is more understandable.