There's a difference between capturing something that was never meant to be captured, and cheating to access a location that was meant to be accessed in some way. At least with the Mew events and such, they were intended to be accessed at some point, whereas the uncatchables were never meant to be captured.
Different people have more and less access to the events, and yet the uncatchables aren't available for capture for anyone at all, unless they cheat. Surely you can see which one is more unfair. :/