It's a good example of how ambiguity can arise when humans use (or don't use) punctuation and other features of a language that's been evolving for centuries, to communicate across an instantaneous worldwide medium with little effort

Well said.

They didn't interpret it correctly, and there's no rule stating a comma is necessary that's universal in every style-guide.

They interpreted incorrectly per English grammar. We don’t know whether they interpreted correctly or incorrectly per the utterer’s intention, as the utterer has not clarified their intention.

This isn’t a question of style, but one of grammar.

It's not that simple. Commas are lawless.

Precisely.