LLMs generate statements that are not *known* to be true, which is different from them not being true. 2 + 2 is still 4 even if an LLM told you that.

This would mostly just be whining about grammar except that mixing up knowledge and truth actually has consequences for effectively conveying meaning in this case: people will interpret “not true” as meaning “false”, and then dismiss the argument as bad faith or ignorant after testing it.