They put these flags up like this for the same reason Mormons and Jehovas go knocking on doors. It’s not to spread the word or convert anyone, it’s to reinforce the “us vs them” mentality that locks people into relying on their group and distrusting and rejecting others.

They (the people who’s idea it was to start doing this) know that the flags are going to get removed from lamp posts, telegraph poles, road signs etc but they get people to put them up and say “look how much everyone hates us” and then all they talk about is how you can’t show the flag anymore because of woke, when most council buildings already fly the union flag and on private property you can fly whatever you want (generally).