This is reductionist to the point of uselessness. People "know" tons of crap, and singular known facts don't dictate behavior by themselves, no matter who you are. Every tradeoff you make is a result of all your collected experience and knowledge on the topic as well as your desires and the complexities of time-based decision making (bad now = good later, and vice versa, where the "bad" and "good" things are never quite comparable qualitatively).

Education affects humans, and education can be changed to better affect humans, but humans can't simply be changed except by education, so it's the ultimate irony to look at people doing a bad job, their fault or not, and imply we somehow can't or shouldn't use the one and only tool we have to change people. Giving up is easy, especially if it's strangers you're giving up on and you don't care about the entire picture of the society you live in. Bettering education is very hard. Taken together, it's obvious why so many people just want to say "they deserve it" and no longer think about it.