Your post is clearly an example of "You said X, so you mean worse Y??" In general, you should try to engage with X and not invent your own Y.
As I previously wrote working so much you can't talk to your kids is not typical. Not every multiple job holder has kids, not every multiple job holder has multiple full time jobs, not every multiple job holder lacks ten to fifteen minutes a day to talk with their kids, some multiple job holders have spouses/parents/etc who can talk to their kids on their behalf, some multiple job holders could afford to work less.
I don't know, but I suspect the previous reply comes from someone not in the situation they're describing. That is - the basic question I posed is how you could not know that your kid's school was bad. A response was that poor people had to work so many jobs they have no time to talk to their kids and I responded in turn by explaining that no, that's not the answer. I suspect the respondent is not particularly poor and isn't even explaining his own situation.
Now, as for what my point is - my guess is that the modal reason people don't know how bad their kids schools are is that they aren't evaluating what their kids learn. I think that's bad and I'm trying to shame that behavior. Parents should be involved, should be tracking what their kids learn, and should be doing something about it when problems arise.
I think attitudes like "some people have to work multiple jobs so we can't blame parents for being complacent with the poor public school system" are bad.
Going back to what I wrote about the previous commenter not being in the situation he's describing - I think it's a common pattern for the rich to give bad advice to the poor. "Oh, you poor poor person, don't worry that you don't know how your children are doing at school, it's probably because you're so busy working! This isn't your fault, etc etc". I would say that if you don't know how your kids are doing in school you are failing as a parent and should immediately correct that. Education is vital to improving your child's circumstances and if you want a better life for your child you should do your best to insure your child is well educated.
Again, just going off guesses, I bet the previous commenter holds himself to a higher standard. He won't ignore the education of his children, but will defend others doing so - assuming they're too busy to pay attention.