you're not wrong, and the picture doesn't really make for an easy positive ID, the only reason I say vorticella with such confidence is that I've spent a fair bit of time examining them closely recently and what's depicted in the OP appears exactly as they do in my daphnia and moina cultures just slightly blurred.
If paulsballs returns I do agree there's no need to panick about shrimp, I MUST have been introducing these to my shrimp tank along with daphnia for quite a while and none of them seem to be afflicted. You wouldn't expect Vorticella to thrive in most aquariums, I think there'd need to be underlying problems for it to become a serious issue for shrimp and they can be fairly easily cured with minimal risk too.