Someone once asked me how to deal with spammers, trolls and others who they didn’t want to read their blog. If you are self hosted it is possible to block the IP address(es) of people you don’t want to visit but that has its limits.
There are lots of different ways to get around that so there are really only a couple of ways to prevent those people from reading your blog.
Password protect it so that those without the password are unable to access it.
Shut down your blog.
Block and or email those you want to go away and ask them why they insist on showing up where they are unwelcome.
These are not ideal methods but those are the ones that come to mind. The reality is that once you post your words you lose control of them.
It is not much different from the loss of control that comes from sending an email. Over the past few years some emails were forwarded to me and I gained access to information that I might not otherwise have had.
In some respects that is a double edged sword as I received confirmation about the duplicitous actions of someone I know. But it also upset me and I have wondered if there ever was a reason to let them know I know about certain things. They could deny it and I could send along the email they wrote.
Would it serve a purpose? I don’t know that it would.