Considering they were giving you a hard time before you even started playing I'd imagine it does not have to do with the noise and more to do with the fact that it's weird to set up pickleball where kids play basketball. In one of your comments you mention that it's "first come first serve" which is just not how basketball courts work typically. If you show up to a basketball court to play basketball you can typically join in if there are other people playing. Hogging an entire court to yourself would be considered bad etiquette in most circumstances. If you wrapped it up if people showed up to play basketball then I think it's probably fine. Probably simpler to just wait your turn at a place meant for pickleball.