As the title suggest, i want to get rid of certain follows so they cannot see my post or activity anymore. 

Blocking won't help because it only blocks me from reading the followers posts. 

Because followers can harass you.

Potentially yes. Guy A started a thread lamenting about the author of a game being late with update. I asked the Guy A to be patient and consider that the author may not be able to be on point cause of real-life-Problem, delay being a normal thing. I  also hinted at problems of the authors supposed country. 

Then Guy B comes out of nowhere, claiming to live in this gigantic country and starts to write a wall of text with a mix of "dating", "being offended" , propaganda and accusations. I wrote a clear "No, thanks and goodbye". But instead this Guy stated to follow me now.