pokemon showdown is insanely and I mean insanely successful but it seems to have been almost blessed by the pokemon company. I genuinely don't know how its leg

pokemon showdown is insanely and I mean insanely successful but it seems to have been almost blessed by the pokemon company. I genuinely don't know how its legal, when I shared the link to pokemon showdown to one of my friends, his first thoughts was, wait how is this legal? This is such a good thing, I wonder why this is free. Only for me to tell it its open source and bro was flabbergasted to say the least.