The original 251

[...]
幼稚な - childish, innocent, babyish
キディ- kiddie

and even if you wanna bend over backwards and claim they are exclusively referring to the official "baby pokemon" (they aren't since for that the japs would have used the expression ベイビィポケモン) you can tell how much of a jump it would be from everything else in

>The original 251
there is no such thing

>"I see. Most Pokemon in Gold & Silver were of the cute variety, but this time…”
>Sugimori: “Indeed, there were a lot of kiddy designs, and some fans were starting to say Pokemon had become too babyish, so one theme for Ruby & Sapphire was returning to the coolness of monsters.
>“In your previous interview at the time of Gold & Silver (February 2000 issue), you said when you were designing Pokemon, you had to consider merchandising, and that created some constraints.”
>Sugimori: “Rather than constraints, I’d say we were careful about a lot of things. Like we’d say ‘if we don’t make a Pokemon this way, they’ll be difficult to animate in the TV show.’ We didn’t really think about those kinds of things this time, which might be bad for the anime staff and independent artists.”

to

This is a mistranslation from Johto haters, here's what he actually said:

>"I see. Most Pokemon in Gold & Silver were of the cute variety, but this time…”
>Sugimori: Our priority with Pokemon has always been to create an even split of ‘cute’ and ‘cool’. But at that time, the breeding mechanic was a heavily advertised new feature in Gold & Silver, and so there were many ‘baby’ Pokemon created to showcase this. So even with the many ‘cool’ designs of those games, we felt that the audience would misinterpret this as an imbalance. So for Ruby and Sapphire, we had to ensure that this notion of imbalance did not reoccur, and we ended up making a lot of cool new designs.
>”When you were designing Pokemon around the time of Gold & Silver, where you now taking merchandising into consideration, and did this ultimately cause any constraints for the new designs?”
>Sugimori: “Rather than constraints, I’d say we were careful about a lot of things. Like we’d say ‘this Pokemon is cuter/stronger, so it should act like this’. However this time we didn’t really dwell on this too much.”

the mistranslation gay

This is a mistranslation from Johto haters, here's what he actually said:

>"I see. Most Pokemon in Gold & Silver were of the cute variety, but this time…”
>Sugimori: Our priority with Pokemon has always been to create an even split of ‘cute’ and ‘cool’. But at that time, the breeding mechanic was a heavily advertised new feature in Gold & Silver, and so there were many ‘baby’ Pokemon created to showcase this. So even with the many ‘cool’ designs of those games, we felt that the audience would misinterpret this as an imbalance. So for Ruby and Sapphire, we had to ensure that this notion of imbalance did not reoccur, and we ended up making a lot of cool new designs.
>”When you were designing Pokemon around the time of Gold & Silver, where you now taking merchandising into consideration, and did this ultimately cause any constraints for the new designs?”
>Sugimori: “Rather than constraints, I’d say we were careful about a lot of things. Like we’d say ‘this Pokemon is cuter/stronger, so it should act like this’. However this time we didn’t really dwell on this too much.”

isn't even translating things wrongly, he's straight up making shit up