I am betting he was told the real reason but he chooses to make his own assumptions about the landlord’s motives. The real reason may very well be that he flew the flag and it was in the lease not to fly flags. Some homeowner’s associations have rules about no flags, no signs, so if he was in a complex, this could also be a reason. He’s going to have his own paranoid reason about why he was evicted. Who knows, maybe he was late with the rent, or maybe the landlord wants to put a friend or relative in the house.
Friends of ours live in a tight community where one of the houses flew a giant “Fuck Biden” flag. It upset the other homeowners, not because they did or did not like Biden but because it had the word “fuck” in it. It made the neighborhood look shitty.