That was my interpretation at first too, but their anecdote about being heard from inside a car leads me to believe they're talking about cars seeing/hearing them on the road for safety reasons.

Is that the reason they rev up their engines to the breaking point while standing in traffic?

That's the biggest annoyance in my eyes. As a motorcyclist, i think its ok for the engine to make some noise (not counting the obnoxious cruisers or bike with some aftermarket exhausts), but there is truly no reason to rev up hard while sitting in traffic or in a slow central streets.

A loud bike has the benefit of being a giant "f you, I'm an antisocial idiot" to pretty much all the innocent passerbies, race colour gender political affiliation OS preference aside :). It shows to others exactly what your post does so succinctly.

You should be treating people like people-not limited terms like “liberal“, “conservative”, or anything else. People are people. Ends unto themselves. Not means to an end, such as whatever calling someone liberal allows you to do and feel.