Thank you, I'm well aware of the technicalities and what you said in the other bullet points. While no, my handle does not make me identifiable, it is something I can't change (though I would), and it does bother me as it something I use elsewhere, too. Unfortunately, I'm also aware that this affects me differently than it affects you (and it pretty much doesn't).
So no, this is no solution for me, but if there's nothing to do, I need to give up. If I turn the question around and I ask, 'can I request the of my personal data on this site?', would it make a difference?