Hm, thanks for correction. I'm definitely not an expert. I just vaguely remembered that it was something that was at one point being legally challenged, so looked it up and found those articles, with headlines including:

"Supreme Court rules that building codes cannot be copyrighted"

"Construction code purveyor calls Supreme Court's ruling that annotated code can't be copyrighted 'monumental'"

Are you saying those headlines were overstating?