Whether you like it or not, it's perfectly correct use of 121.5 in UK airspace.
If something like this really does make you furious, I suggest you take advice from a aviation medical practitioner, because it sounds like you aren't coping too well with what is a fairly normal situation.
Alternatively, simply deselect the frequency at critical times and switch it back on a few seconds later when other people have finished talking.
Seriously?
