In Spanish and Portuguese "mal educado" == literally "poorly educated" is used to mean "someone with poor etiquette ... doesn't know how things should work" ... writer probably means in that sense.

Perhaps they mean "uneducated in riding public transport in a way that doesn't hassle other passengers."

Anecdotal I know but from what I've seen they probably know they should put their backpacks in front, they just don't care. I went to a museum once where patrons were asked to either wear their backpacks in front of them or lock them up near the entrance. Literally almost everyone disregarded those instructions and put their backpacks on their back despite being asked directly multiple times to put their backpacks in front. They would for a quick second then move them to their back once the museum staff looked away. It was a real eye opener on people's self centeredness.

He meant "uneducated" on how to behave in the tube. We would say the same thing in Europe if somebody is walking on the wrong side of escalators or similar, it doesn't mean we are literally saying they are uneducated.

Thanks, I'm unfamiliar with this usage. It was an honest question, don't know why I got downvoted.