The Gadsden flag, the snake, was a patriotic symbol during the American revolutionary war.
The snake in general was a common symbol used at the time with a famous (Franklin?) illustration of a snake in 13 pieces representing how the snake needs all 13 colonies to be whole.
The Gadsden flag was the “13 pieces of the snake united, coiled and dangerous” with its “don’t step on me” motto. This flag despite being anti-government oppression was actually supposed to represent the strength in our unity (sad they now use it to divide).
The blue line flag is part of a movement that implies that the police are the only thing holding back chaos from society. It’s designed to mean the flag only exists because police keep society existing. This has and was always been a load of shit but now has moved more into meaning “our side is the side who makes stuff work” and sliding even further into a fascist strongman style ethos.
Both are now effectively just “brands” of the American conservative right.
The thin blue line flag is supposed to support police, the weapon of the state. But the Gadsden flag represents that “they can’t or won’t be oppressed.” The Gadsden flag made a big comeback during the Bush years and the spread of a more “(what they called) libertarian” sect of the American right. Which frankly is bullshit because it’s an American symbol not the hate symbol they’ve coopted it into these days.
It’s a grab bag of US conservative branding but all in all on the surface you can make a measured bet that this person complains very hard about the taxes other people pay, don’t understand civics at a fundamental level, and likely while pretending they aren’t they are supremely racist.
You could equate these two flags to be the equivalent of someone flying a Thor Steinar logo flag in europe.
A better idea of how dumb this is would be imagine someone driving down the road in 2250 flying a Brexit flag and a EU flag on their truck