Campus PD's are always, without exception, mostly composed of cops who somehow couldn't make it into a city police force. Their incompetence to be expected, regardless of what university you attend. It's when the local city or county police force starts playing God that reasonable people start getting pissed.
Of course not every person in the RCPD is a bad apple, just like every department in the country, but there appears to be a directive from the top to enact a form of Prohibition amongst college students, despite official statements to the contrary. There may or may not be a moral aspect taking part in these decisions to harass a group of people that constitutes little more than a minor public nuisance in a majority of cases; it really could be a number of factors. Perhaps the police department's actions are an extension of mistrust between the students and the overall community of Manhattan. Students don't often vote in local elections, so townies can often use their clout to have the police take out their frustration on the students instead of trying to open up a collective dialogue. This happened to such an extreme at where I got my undergrad that extremely heavy-handed tactics implemented by local police incited near-riots in the early 00's. Another factor may be a vendetta carried by the head of the department, who has gone on record as complaining about not getting enough of a raise despite tough city budget conditions. Maybe he is directing RCPD to hand out extra citations to try and concoct an external "threat" that cowers City Council into giving his department more money. Maybe the crime rate is just so low that they don't have anything better to do than to harass college students. All of these factors can happen and have happened in college towns and other municipalities across the country.
Also consider that the public knows that police departments almost always deny policies or actions of officers that may be considered unpopular or illegal. You and I both know that the vast majority of police departments would rather "stick with their own" than punish a bad apple for a particularly egregious act. How many news stories have you read about a cop using unnecessary force and receiving paid leave, only to be back on the force within weeks or months? Police departments are also becoming increasingly militarized, taking on a "siege" mentality, and responding with disproportionate force to minor and non-violent offenses. Given these trends among police in the country and the tactics that specifically RCPD has taken recently, I don't understand why or how students at couldn't hold at least a little bit of mistrust for them.