The different treatment is injury and death vs slight inconvenience. It's an asymmetrical arrangement in favor of the car for any kind of two wheeled conveyance. Or are you fearful of ten-speed riders traumatizing you by impolitely smashing up on the windscreen instead of politely disappearing under the wheels?
You are not wrong though. It just is not a defensible position. You won't be the one who suffers.
You're missing the point. What matters is that GP's friend had used "activism" to describe acts of simple spite or revenge, and the label does not apply. Such behavior stands in the way of real activism. Perhaps you feel the spite is deserved, the revenge justified, based on the level of potential consequence. Your use of hyperbolic imagery and character assassination suggests that you might, and I might not even try to dissuade you ... but don't call it activism. Words have meaning, and a potato is not a pear.
You are not wrong though. It just is not a defensible position. You won't be the one who suffers.