The yellow and black flag is the ancap (anarcho-capitalist) flag. The rattlesnake is a libertarian icon and says "don't step on me". Bitcoin was built out of a libertarian idea that the government was to blame for the 2008 GFC because they somehow regulated the banks too much, so a decentralized digital currency was the best way to get around that regulation. ETA: the black and white US flag with the blue stripe is the "thin blue line" flag, flown by supporters of the police, typically a symbol used by the right wing of America. The three interlocking triangles form the valknut, a symbol used by ancient Germanic people's, and currently used by people who identify with Germany and the Vikings; white supremacists make up a large group who fit this description.
The red and black flag is an anarchist flag, a combination of two older anarchist flags: the black flag and the red flag. The ancap flag is descended from this one, replacing the red with gold (because gold is a very old and widely used form of currency, and money good, government bad). The purple and black one is the anarcha-feminst flag, and they also use the pink and black flag, but it's primarily seen as the queer anarchist flag. I'm sure I don't need to explain the LGBT+ flag. All Cops Are Bastards (ACAB) is a popular slogan amongst anarchists because cops are the strong arm of the state, and as such Black Lives Matter is a movement that a lot of anarchists strongly identify with and support.
There's two types of military SONAR: active and passive. Active SONAR is using pings and listening for the echo, but it's not very commonly used by submarines. Passive sonar is just listening out for engine noise from ships and prop noise from other submarines. Warships use active SONAR more because they're already noisy and so if they think an enemy submarine is in the area they'll use it to try and locate, but in peacetime it's mostly reserved for training exercises. It's still terrible for wildlife, even if they don't die it's very distressing and disorientating but it's not constantly scanning like a RADAR.