They don't merely "have polices powers" - they are police.
Yep, I get that. My objection - if you want to call it that - is that a university police officer was evidently stopping someone on a public street for a relatively minor violation. I'm not questioning the legality of that. I'm questioning the sensibility of that.
If I were the university president, I'd sure want my officers on campus, protecting students. It's a minor thing in the greater story here, I know.