I agree with the other points but this one doesn't quite work. It also can be abused and has been by some already. Besides, ti's literally impossible to harass anyone on a forum, makes no sense.For example, harassment means to continue to attempt to engage with a member after they have blocked you and asked you to stop contacting them.
If someone uses the Block function, they block others from tagging them and using the PM system, right? So, that person cannot be contacted anyways. This should not stop anyone from continuing to respond to their posts. All this does is allow the person using the Block function to block anyone who doesn't agree with them.
Continuing to respond to their posts is not harassing them at all, especially when they can't tag the person or contact them.