This is Bait
I'm afraid you've been click baited. I will not be arguing for or against HTML's status as a programming language. But now that you are here, can we spend a minute pondering why it's so important that HTML be classified as a programming language?
The Value of HTML
The issue that I have with this argument, is I feel like certain groups of people feel as though without classifying HTML as a programming language, you are somehow doing a disservice to HTML as a skillset or the people who either make their living in-part by writing HTML or those who only know HTML.
HTML is a critical skill. Let's go ahead and establish that now. Even if you work in a framework like React where you are writing a superset of HTML (eg. JSX), HTML is still the magic that actually makes the web what it is. Without it, every single website would no longer exist.
Tech is not Exclusively Programming
The issue with the implication that if HTML is not a programming language, then it is somehow not valuable and the people who use it are not "real programmers", is that it leaves a whole lot of people out in the cold.
The modern landscape of development, whether that be for the web or any other platform, is a dense community of very diverse skills that must work together to create the internet as we know and love it. Some people write code, but other people do not. The latter group is just as important.
A Few Examples
People writing documentation for a framework, library, or product
Without these people, all knowledge of how a tech or product works has to be figured out through trial and error, taught one-to-one from knowledge keepers, or just never discovered. Products have literally failed just because of this one shortcoming.
People building infrastructure and automations using configuration languages
The internet may be held together by cooking twine and craft glue as people like to say, but it still works a majority of the time and the majority of the infrastructure is created without "writing code". Some people still build their infrastructure manually with GUI interfaces. Without this effort, it doesn't matter how great your code or product is.
People designing UX and UI
I won't speak for all developers, but I couldn't be trusted with making a flier for my band to play at the local dive bar on 5th street, much less a fully featured web application optimized for ease of use and accessibility. Designers are brilliant and multi-disciplined people and without them, the internet would still look like Tim Berners-Lee's website.
I considered adding more examples, but fear I am on the edge of beating a dead horse if I have not reached that point already. The key take-away here is, however you feel about the classification of HTML and what sort of language it is is totally fine. Just keep in mind, when you imply that someone saying "HTML is not a programming language" devalues people who write HTML, that the opposite also devalues anyone whose job does not involve writing code.