Pokémon Gender Discussion

So, Pokémon were originally referred to without gender in the Japanese language, besides some like Nidoran. Why do we currently gender Pokémon—even those that are « genderless/gender unknown » ? I mean, they’re not really humanoid and have very different characteristics from animals. To put it into perspective, what if someone said, « I caught a Raikou! They have high IVs and I got very lucky with them. » rather than, « I caught a Raikou! He has high IVs and I very lucky with him. » Thoughts? Thank you.