If you haven't seem them in an urban environment, it can be hard to explain. They are not like bikers cruising on a country road.
They are on dirt bikes and ATVs, no helmets, popping wheelies, swerving all over the road. Traffic has to come to a standstill while they pass.
I have seen it so many times it doesn't fluster me at all. I am not trying to be a Karen over it; people in Baltimore do crazy stupid shit all day every day. This is one of their milder outlets, honestly.
There is also a darker side behind it involving theft of bikes and ATVs and basically what amounts to a black market chop shop environment.
It is what it is. Better than murdering each other, I think.