The post you quoted never said bus shelters it said bus stops, which to me are two different things. Private companies do clean the shelters but i haven't seen them clean a single bus stop, even though no doubt several dogs have peed up them.
Also, isn't it local councils who contract these companies out to clean the shelters, take flyers down, etc.? Surely it wouldn't of hurt this person who took the posters down to contact his bosses or the local council to ask if it was ok to leave these posters up? Don't they have a conscience? A jobsworth possibly? Poor Liam hasn't been missing a month yet, it's insulting to take his posters down already.