Don't people just need a ga activated to create pets after getting slots and not having to have one when buying slots?

In short, yes. For anything more than your basic blue-account 5 slots, you'll need a gold account no matter how you gain the extra slots-- or so as far as I know. Tbh, this seems a little unfair but I guess it's not likely to change any time soon...

wait so you mean when a person buys the slots they have to have a ga active?

Not as far as I know, you only need the GA to actually /use/ them.