Hah! That interpretation didn’t even occur to me, but yes that makes more sense.

No, we have tone and punctuation to disambiguate the two interpretations here. Parent commenter interpreted correctly. If the grandparent’s intention was otherwise, they should have used a comma.

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.