Yes. It's abuse because Uber presumably have a lot of bikes they would like to inject into the system. Every bike displaces one available parking spot.

Suppose there's a small town with one bike lot at the library. Everyone keeps their bike at home except to go to the library. Does the use of those bike spots affect the public? Yes.

Would it be okay if Enterprise Car Rental used public spaces to hold their inventory? No. That's not how rental companies work.

Perhaps there is no law, but I expect that to last about ten seconds after Uber pulls this stunt.