This is true. There are people who hate the police. Sometimes they have good reasons to do so, such as bad past experiences with police; sometimes they are criminals who regard police as the enemy; and sometimes they’re just angry people (often angry white people) looking for something to hate on. Their behavior doesn’t always make sense.
I think there are always going to be a significant number of kids who look up to police officers though. I have no idea why, but they do. At the height of all the police brutality incidents during Obama’s second term, I was handing out candy to trick-or-treaters and a couple boys came dressed as police officers. They were old enough (like age 8 or 9) that they would have chosen their own costume rather than their parents picking out what they would be. I was a bit surprised because the police were getting nothing but bad PR that year and yet kids still wanted to be a police officer for Halloween.