Not to "true scotsman" this, but the egg prime directive isn't saying you can't have those conversations with people.
This person notably didn't say "my trans friends told me I was an egg, so I tried HRT just to shut them up." It sounds like they were aware it was an option through conversations where it wasn't pushed at them. This person made their own choice.
The egg prime directive is saying that you don't get to declare someone else's identity for them. You don't get to make that choice for them. It's about consent.
I think most of us would agree that it would be abhorrent to tell someone who is asexual that they just haven't found the right partner yet and clearly they're homosexual (or straight or bi) in denial. I see it as the same thing.
And the online culture of labelling other people as eggs is so far removed from the concept of "trying to help someone figure out who they are" that I have a very hard time taking this in good faith. C'mon, of course there are different rules for socialization online vs in person vs with friends.