It's really hard to find the "In Room" section of the big menu, but indeed the information is missing from both places. This information allows me to know while talking to someone that they aren't able to see PC content.

If there was content and feature parity on both platforms, I would agree that "judging" would be the chief concern here. But right now, there is a great disparity between what PC users and what Quest users see or are allowed to do in some cases.

Knowing that you are talking to a user on a different platform is vital in order to make social decisions which are inclusive to the other platform. For example, without this knowledge, how can I decide whether or not it is appropriate to drop a PC-only portal?

Or, when the Quest user is using an avatar which is broken or laggy on PC but well-optimized on Quest (these are sadly quite common), how can I know that what they see is different than what I see?

Or perhaps I have something on avatar which I'd like to show, but perhaps I can't because all common methods of locking something in place in the world are forcefully disabled on quest avatars with no option to override. Knowing that they are unable to see that content, even if they click "Show Avatar" is good to know.

Or perhaps I'm in a world which is missing a room on the quest build for optimization reasons (these worlds exist) and I need to know that I should move to the spawn area so that they can participate.

amazing. you just described why its no longer there