Client species are indentured for 100,000 years, in exchange for being uplifted; they used hyperspace shunts as a sort of testing ground for sentience; with the ministry of uplift or whatever it was overseeing things.

If patron species were able to be embarrassed or abused the client species, they could be freed from that (which was the motivations of the Pring in sub diver; discrediting the Pila meant being able to get freedom,)

Humans didn’t have that rule or mindset when they uplifted dolphins and chimps; since it was still before contact with galactic society; it wasn’t until space flight that we found out about any of that.

It’s also important to note that humans were odd and contrary to galactic norms; being Wolfings, we bootstrapped our selves into space.

Which was a defining technology for GalCic- unlike literally any other species, we sought to understand what we used and tended to avoid using things we didn’t understand.

A central belief is that everything has already been invented; so why bother. This meant everything was recycled tech; with races finding ancient tech in the library and using that instead of designing new.

This made humans unpredictable, in a society that highly valued order.

Having 2 clients as well, meant a 3rd would give an incredibly young, utterly unpredictable race highly influential standing politically and socially. (It’s probably best to consider patron/clients as a cast system;)

Humans- and earthclan in general- were not liked simply because the galaxy did not like change. It had been stagnant for hundreds of thousands of millennia.