This is mostly true, but the asterisks cause a little chaos.
> HTML is the semantics ... the element tag to say "what it is"
Maybe this is best framed as a perspective thing.
"Semantic HTML" is about HTML authors using HTML elements in a way that is consistent with the definitions laid out in the specs. These definitions try to specify element semantics because user agents want to be able to do less-dumb things (things that don't work as well if HTML authors are constantly abusing tags for some presentational effect even though the semantics are weird or wrong).
The main consequence of this is that tag semantics (from the UA's perspective) won't always square with what the author assumes it means unless they go study the spec. For example, it's probably not hard to go find cases where the <address> tag is used for the obvious thing from the author's perspective: marking up addresses. The spec, however, explicitly contradicts this surface-level reading: https://html.spec.whatwg.org/multipage/sections.html#the-add... (i.e., it can be "correct" for pages to contain a mix of addresses that do and don't have the address tag.)
We also have a lot of tooling that invites semantic abuse for presentational effect (i.e., using markdown blockquotes as notes, and even the fancy behavior browsers attach to the <details> element).
> HTML is the semantics ... the element tag to say "what it is"
Maybe this is best framed as a perspective thing.
"Semantic HTML" is about HTML authors using HTML elements in a way that is consistent with the definitions laid out in the specs. These definitions try to specify element semantics because user agents want to be able to do less-dumb things (things that don't work as well if HTML authors are constantly abusing tags for some presentational effect even though the semantics are weird or wrong).
The main consequence of this is that tag semantics (from the UA's perspective) won't always square with what the author assumes it means unless they go study the spec. For example, it's probably not hard to go find cases where the <address> tag is used for the obvious thing from the author's perspective: marking up addresses. The spec, however, explicitly contradicts this surface-level reading: https://html.spec.whatwg.org/multipage/sections.html#the-add... (i.e., it can be "correct" for pages to contain a mix of addresses that do and don't have the address tag.)