Reading (A) and (B), I cannot help but notice that it doesn't matter whether the primary purpose of the circumvention is to infringe copyright. It is enough that the software/service is primarily about circumventing the "technological measure".

The technological measure itself doesn't even have to be primarily about preventing copyright infringement. It suffices that it effectively controls access to relevant works, even if it's not its primary purpose.

We could even argue that YouTube's restriction are primarily a means of getting people back to YouTube, with copyright enforcement being only a secondary concern. Sadly, this argument would be irrelevant with respect to (A) and (B).