Thanks for asking, NuclearPM. It was not actually a question. In informal English a question mark can follow a plain statement, where then it indicates a non-specific uncertainty. In the case above, the sentence could be interpreted generally as: “I didn’t say they were... and I'm not sure what gave impression I did" or "I didn't say they were... I think you misinterpreted."

Does that make sense?

I fucking love how the fact that English is totally, totally, literally non prescriptive breaks engineering type people’s brains.

Perfectly fine use of colloquial commenting?

Yes.

Against the ‘rule’ you were taught in primary school English? Also yes.

That’s why English is so interesting.

English be like this man. It's everything all-in-one. Fascinating language I tells you. Much like all other languages which be fascinating.

I would argue against the siblings and say, yes, it's a question; it's a shortening and softening of the rhetorical "But then I didn't say they were, did I?"