Obviously can’t say for sure from your account, but if you cannot see how those guys knew what you had done, I would assume the following.
They are plugged into something most people know nothing about, that sees a lot of stuff, and is probably anti-Trump because he was a target of it, and is moving to cut its influence. That is probably what is up with the flag. They were firemen second to “it.” It can become a pain in the ass if you deal with it, so inflaming things with it could become a headache.
I would drop it. Let sleeping giants lie. You may really have no idea what you brushed up against, trust me.
Yeah, I’ve gotten tired of analyzing it, and I’m decided that I’m not going to report them to their fire chief. Probably more bad than good can come of it. They were either:
a) clueless and didn’t understand what an inverted flag symbolizes
b) didn’t believe me that it was inverted and just saw me pulling down the flag
c) actually believed it was a protest against Trump’s enemies (preposterous)
d) they are union #resistance thugs
D is the most likely possibility based on the interaction but A and B are conceivable, so it’s not worth getting them disciplined based on that, plus the risk exposure to myself, even though they tried to chase me through a residential neighborhood in a damn fire truck and could have gotten someone injured or killed.
I think one person suggested that maybe it was originally flown right side up and that some saboteur snipped the top zip ties, but that isn’t likely. I ride this trail all the time and most likely would have noticed it.