Redefine the way block works for threads

Problem/Motivation

When a user A is participating in a thread and blocks someone in that thread, the user A will loose track of that thread, like if it didn't exist (it can only access to the thread if it uses the URL!!). It will also loose track of all the threads that the blocked user participates.

It seems like the blocked user is the one that blocked someone!

Proposed resolution

The user A should continue to access all threads.
It should not read the messages from the blocked user.
But I think the best would be to see them obscured. I consider important to be aware that a message was posted in a thread.

Remaining tasks

It's also important to understand how the Passive/Active blocking works for threads.