I am, frankly, as croggled by this characterization as I am by why you feel insulted and saddened by WotC handing the keys of their major RPG setting over to you.
Saying "Actually, I think this is a good thing and I don't understand the mindset that finds being empowered upsetting" isn't lack of compassion. It isn't gloating or reveling in your pain. I understand and accept that you are hurt and that your hurt is genuine, if that's what you want to hear; please, accept my permission, if you want it, to feel your feels. But the perspective that sees endless possibilities and freedom before you, none of it superseded from on high, and feels hosed because of it remains mind-bogglingly alien to me. Feel free to explicate further on your perspective if it will mend whatever failure of empathy that implies on my part.
Except: it's still not cool to say "I get to complain about this as much as I like, but you can't be happy about it." You get to feel your feels; you don't get to police mine.
The guy just asked you not to be so gleeful about your victory mate.
If anyone wanted to write a Forgotten Realms fan fic then they always have been able to, just like I can get a few mates around on the weekend to play Superbowl Football. But I have never actually seen anyone complaining about that.
Is that really what you think people are upset about?