Most of this has to do with presentation. If someone politely asks “I’m really sorry to bother you, but I can’t find any place for my large roller bag. I hate to ask, but would it be possible for you to put your backpack under the seat so I don’t have to go through the hassle of gate-checking my bag?”

if you TELL me to accommodate you, there’s a problem. If you ask politely, I’ll jump through hoops to help you.