When everyone uses it, then the share of regular people who just want to go somewhere instead of harassing others gets up. But if only marginal people take public transit, then of course you'll mostly encounter marginal people there. The problem is how to start making everyone take it again.
Here, children are driven to school by their parents. When school ends, the parents are there waiting in their cars. Kids mostly don't even play outside anymore.
Those of you thinking public transport is fine are likely at least a little bit physically imposing and/or you are in relatively fancy locations.
Conversely, are there large cities in other countries that are similar to the US, where this does not happen? I'm going to suspect the Middle East, due to ubiquitous air-conditioning.
When I moved to London for university, there were 5-6 year olds on buses and trains, accompanied by an older sibling. And they were the rich children attending the private school I lived close to, normal children that age would live close enough to walk to their local school.
Yes, GP appears to be ill-informed about how kids get to school in large parts of the US. In NYC, students take public transit (and are provided passes, if necessary) from approx 13 years old. The same concept applies in most cities I know of on the East Coast (I can't speak for further west, though it appears Chicago has a similar system).
Obviously if people took the time to look at the crime statistics, the chances of being a victim of a crime is less than half of what it was when I walked a mile to elementary school every day.
For more normal crimes, the lifetime chance of being a crime victim is serious. For stranger-on-stranger violent crime, there is a total lifetime probability of about 5.3%.
You might think "oh that is just 5.3% so no big deal", but the chance of dying in a fire is only 0.09% and we still bother with smoke detectors.
Violent crime is a life-altering event. Given the potential for horrific consequences, it is reasonable to be concerned about the possibility. Transportation choices change that risk.
Do parents get out of their work in the middle of the afternoon to drive their kids from school to home? Do they go back to work for the last couple hours after that? Or do kids have 8-hour schooldays?
Some people have fully flexible time. Some people have a part-time job or two, so they simply don't agree to work shifts during the times they need to drive the kids around. Some people don't work, often because a single income is supporting a two-parent household.
It might have been better if the addition of woman to the workplace included an equal shift of men to a househusband role.
PS I like your username.
And I did stayed some time while the kids were small and disliked that a lot. You get used to depression as a normal state, basically.