Unless something changed in the specification since I read it last, the attested environment payload only contains minimal information. The only information the browser is required to send about the environment is that: this browser is {{the browser ID}}, and it is not being used by a bot (e.g. headless Chrome) or automated process.

Depending on how pedantic people want to be about the definition of DRM, that makes it both DRM and not DRM. It's DRM in the sense that it's "technology to control access to copyrighted material" by blocking bots. But, it's not DRM in the sense that it "enables copyright holders and content creators to manage what users can do with their content."

It's the latter definition that people colloquially know DRM as being. When they're thinking about DRM and its user-hostility, they're thinking about things like Denuvo, HDCP, always-online requirements, and soforth. Technologies that restrict how a user interacts with content after they download/buy it.

Calling web environment integrity "DRM" is at best being pedantic to a definition that the average person doesn't use, and at worst, trying to alarm/incite/anger readers by describing it using an emotionally-charged term. As it stands right now, once someone is granted access to content gated behind web environment integrity, they're free to use it however they want. I can load a website that enforces WEI and run an adblocker to my heart's content, and it can't do anything to stop that once it serves me the page. It can't tell the browser to disable extensions, and it can't enforce integrity of the DOM.

That's not to say it's harmless or can't be turned into user-hostile DRM later, though. There's a number of privacy, usability, ethical, and walled-garden-ecosystem concerns with it right now. If it ever gets to widespread implementation and use, they could later amend it to require sending an extra field that says "user has an adblocker installed". With that knowledge, a website could refuse to serve me the page—and that would be restricing how I use the content in the sense that my options then become their way (with disabled extensions and/or an unmodified DOM) or the highway.

The whole concept of web environment integrity is still dubious and reeks of ulterior motives, but my belief is that calling it "DRM" undermines efforts to push back against it. If the whole point of its creation is to lead way to future DRM efforts (as the latter definition), having a crowd of people raising pitchforks over something they incorrectly claim it does it just gives proponents of WEI an excuse to say "the users don't know what they're talking about" and ignore our feedback as being mob mentality. Feedback pointing out current problems and properly articulating future concerns is a lot harder to sweep under the rug.