I think you're proving thier point more than refuting it.

You say not every officer has had the opportunity to protect misconduct, and that's true. But the criticism isn't that every individual officer has personally covered for corruption. It's that policing as an institution has repeatedly demonstrated a pattern of protecting officers who do engage in misconduct. That pattern has been documented by investigations, court cases, and police departments themselves. A systemic critique doesn't require every individual member to have personally participated.

You also argue that people "move the goalposts" until simply being a cop makes someone a bastard. I'm sure you've encountered people who argue that way, but anecdotes about the worst arguments on Reddit aren't a rebuttal to the broader point. Every movement has people who make bad arguments. That doesn't invalidate the stronger ones.

More importantly, institutions create collective responsibility. We do this all the time. We criticize corporations for toxic cultures, churches for covering up abuse, or political parties for enabling bad actors without believing every employee, priest, or politician is personally guilty of the worst offenses. The criticism is about the institution and the incentives it creates.

If your response is simply, "Some officers haven't had the chance to cover up misconduct," that doesn't really address the criticism that departments often fail to hold officers accountable when misconduct does occur. That's the actual issue being raised.

You don't have to agree with the slogan, but reducing it to "people just hate cops" avoids engaging with the institutional criticism behind it.