I had the impression, if Tailwind has one thing, it's a multitude of classes.
Yes Tailwind uses classes. But I think the parent might have meant that Tailwind is not semantic.
From the few I know, the classes are mostly shortcuts to css features (container are one of the exception), which are of course defined as custom classes but they don't create a new layer of (name,meaning) unlike what I assume we were all doing.