I I don't see how a black hole's event horizon can be crossed

[Dale]

the tone was so persistently insulting

It was. We are supposed to be an educational site. That is our stated goal and mission.

I hope my colleagues here can look at your experience and think “would I appreciate a teacher that talked to me or my child like this?”

maybe spend several years reading in meek silence before I dare talk?

Just FYI, it took me 7 years of occasional study to finally “get” special relativity. This stuff is difficult.

You don’t have to be silent during that time. But it is better to just ask “what is the resolution to this apparent conflict” than to propose a resolution of your own.