OP makes the point that UA staff did notice it and intended to do nothing until he insisted. That's just not right. This is one of many reported instances of FAs and GAs avoiding confronting an unpleasant issue. They do have the power but choose to avoid confrontation, ignoring the problem and taking the easy way out. It isn't right when the passenger has to wear the bad guy hat to make them do the right thing. Otherwise, it's SOP...just doing their job as is easiest for them.