I had that debate with the Celtic Chameleon amongst others. She believes the block button is a tool to be used to protect your mental health - which is pretty much the way you've described using it. I see that as too tempting - what begins as setting boundaries descends quickly into arbitrary offence and cultivation of praise.

https://medium.com/feedium/stop-fiddling-with-your-comments-section-5ce48dce45d3

I wrote about it there - and you can see Alison and I going at it in the comments section. I have to be absolutely convinced someone is mentally unwell before I'll warrant using the blockbutton and only as a last resort - however, other people can use it as they see fit; just with the caveat it may not lead society to a great place. As someone who is blocked regularly for holding a contrarian view rather than being a troll - I don't see it as a sign of good faith debating. It allows people to have opinions but never the consequences of their opinions.

One of the reasons I'm so active in my comments section is that there should be some comeuppance to whatever you put out into the world and you should be around to defend it. :o)