You're choosing an overly generous definition of platform.

A surly neighbor, a dreaded personage at church, has limits on their influence based on simple geography. They experience pushback against their behavior via ostracism (exclusion from events and groups) and non-verbal cues (facial expressions, body language).

The same type of character on a massive online platform has the opportunity to reach a much broader audience, aided by engagement-focused algorithms that can suggest similarly cantankerous personalities to commiserate with. There is less opportunity for negative feedback against their opinions and actions, because there are seldom any "unlike" buttons, and bans and mutes are usually invisible to the originator of the speech: they can opt to interpret silence as acceptance.