The thread has a very inaccurate information:
The ignore function removes all listing from that person in the Group Finder and also prevents them from applying to your groups.
If that really works on LFR, that means people that ignore way too much people may have significant longer queue in LFR, because otherwise that would just be prejudicial against anyone you ignore, as at the moment you decide to queue for LFR you’ll be “excluding” all of them from the LFR as well.
This could be potentially be even exploited if someone wanted to “troll” or “harass” someone in game, picking up on someone who they know only play LFr and putting that person on ignore. You can add them to a friend list and see when they’re online (character) and then just queue for LFR to make their queue longer (since the system will avoid putting these ignored people together). The more people you get to ignore that person, the longer they’ll remain in queue.
Anyway, just weird that the piece that is clearly working was stated to not work in the post…
Which I have just shown part of that information is inaccurate or wrong.