They're rubbish bins (or perhaps textile recycling bins, but probably not) specifically for national, regional, and/or local flags.
Edited to clarify: No judgment, I am not making a political or societal argument, just posting about a thing I learned exists. If this post gets hijacked I'll ask the mods to lock it.
American flag worship is a little creepy, honestly.
Religious practice precedes religious belief. The first generation to perform religious practices don't do it for "religious" reasons. They don't really "believe" that a flag is a person and that it fundamentally deserves to be treated like one, they just choose to act that way. But when the following generations are raised seeing adults consistently treat a flag like a person, they DO take on religious beliefs towards the flag. And it quickly gets creepy and scary.
TIL, that's actually make sense
This YouTube channel is an awesome resource for anyone (athiest, theist, alien anthropologist) to understand the effects of religion on the world from an impartial point of view.
Are people supposed to thank the flag for its service before binning it?
I believe that's part of the grief protocol, yes.