I left a comment but thought I'd elaborate here.
No, knowing HTML is not programming - it's markup. Even so, when I help people design CS programs, I'll frequently recommend starting with HTML or at least introducing it early.
It's a gateway and not just to programming.
HTML is pretty easy, you want something bold, you just wrap the
It's also empowering and demystifies the web. Kids can create a simple web page and load it right into their browser.
You can even have them change a live page.
Right click on the top of this page where it says "Musings about…" Chose inspect element. In the "debugger" window double click the text, change it and hit enter. This is just temporary - just reload the page but it's pretty neat for a kid to change an article and then screenshot it.
HTML is also a nice stepping stone towards coding. You're working in a plain text editor by adding special code words to basic text which are then interpreted by, in this case, the web browser.
The big reason for teaching html actually goes beyond this. Next step after learning HTML is having the kids programatically generating web pages in whatever language you're using for the class. I like using Python. This requires a little infrastructure setup to serve kids work but then there are two huge wins.
First, as the kids learn programming, instead of just printing out results, they can make a web site with their results and share it with friends, family, and the world.
The other big bonus is that kids might be able to leverage take these skills to other classes. If the student has a history paper to write, maybe the teacher will accept a history web site where the student can write code to do their analytics and build nice looking tables and graphs with results.
So while knowledge of HTML in and of itself isn't really needed anymore it's still an important part of the programs I build.