IIRC, those events likely would have data that can be distinguished from VC data.
Maybe an event location, which no VC event has, (affects Gen 2 events)
or a move, that no VC event has, (affects either game)
or an OT, that no VC has had. (primarily affects Mew)
Read what I said about it being legal because they can't be distinguished.
Now reverse that saying: that also means that if there was a reason that they could be distinguished, they'll be illegal.
Can't remember off the top of my head, so just assume no retail cart event.
They all have one thing or another that is different from VC gen 1/2.
Importantly, VC gen 1/2 has almost nothing different from the retail games.
Heck, the base games they run off, are exactly the same.
The only difference is extra game code running on top of them (changing Jynx's colour, wireless trading, etc)
With that in mind, think of it this way: if events were exactly the same as encounters that retail cart could obtain innately, would anyone get them?
In any case, when it was warned that events for retails are not legal for VC, those factors were taken into consideration, and thus if warned about their illegal then they are indeed not legal.
Don't need to think too much about it it you cannot comprehend why.
I've already explained when makes them legal or not. If you can't understand it, then all you gotta do is accept it