A lot of people appear to hold strong opinions, but they put no effort into defending their positions when challenged.

When people do this, they make it painfully obvious that they have not spent any time understanding what they believe, and so their defence is to ad hom the other person, or resort to sophistry.

There is a big difference between blocking someone who is in fact harassing you, and calling something harassment because it is opposed to your opinions and you can't defend those ideas after putting them out there.