>>56376928>what legality checks?Legality checks are typically used in more recent gens to prevent modified Pokémon from passing through generations and participating in online battles.
The fact that these Pokémon are only illegal in a generation where there are no checks and for all actual things that matter are seen as legal means that they are essentially legal if you ignore the met location. Your logic would then imply that Orre Pokémon are illegal since they have similar met locations (locations not actually supported in game and merely set to a catch-all, but in this case the IDs are set to values not determined yet instead of IDs that are catch-alls, which act the same).
>GF did not approve/create thisThere are a lot of things that people create which end up passing through as legal in the gens where it matters and are better than what GameFreak creates. What's wrong with that?