Step on a crack...

He gets a new mom in Rugrats In Paris, and a stepsister named Kimmie.

BUT ITS SO SAD WHY WOULD THEY DO THAT TO POOR CHUCKIE

to add realism to the story. not everyone has two parents.
That's why they also didn't do a Christmas special.

But they've done Hanukka ones, since Tommy's maternal grandfather is Jewish. He even speaks yiddish quite a bit throughout.

Exactly.
To add realism to the story.