I've seen some arbitration agreements stating that you can't collaborate with other customers who are affected by the same issue, requiring each customer to have a different attorney.
Oh no, I did it anyways and collaborated with other customers online. Oh well guess we gotta arbitrate that now.
If we're talking about Digital Rights Management, steam is acting in that role to manage your digital rights on the steam platform. They could allow you to download games without requiring an account login or client download, and they instead do not. They could allow you to download free games from the client or the website without requiring a login, and they do not.
GOG's website is also DRM for the same reason. It won't allow you to download games that aren't licensed digitally to your account, including free games. GOG has DRM-free games and installers fairly universally beyond that first check, and that means you can download them from alternative sources, but downloading from GOG 100% requires interacting with DRM.
To be direct: I don't care that Steam is DRM because it's minimally invasive and I currently trust Valve enough to use an operating system made by them as a daily driver. There are very few companies I'd say that about.
The Steam client is DRM at its core, even if it's acceptable DRM. I think it's important not to allow your thinking to shift from the reality that it is DRM just because it's personally acceptable.
I don't mind it, I will simp for Valve all day long, and if a company requires you to log in to an account with their server to check whether your account has the digital entitlement to then allow you to access a file or not, that's digital rights management.