You're wrong. When I need to stay focused on something I may ignore messages and be 100% productive. However when I'm at the office most people don't care if I'm working on something with my headphones on, clearly in the zone. They'll just approach me about the most benign matters most of which can wait for days even.
There are plenty of people who say they don't go to work to make friends, they go to do their job, and any kind of interruption not directly related to the work they're doing is unwelcome. Plenty of others who will go to great lengths to stay out of any conversation and work as independently as possible because "they're just there to write code" or whatever.
If it's not so wrong to say you want to go to work and be completely left alone, why is it wrong to say you actually go because you prefer the dynamics of office life and find it less disruptive than a remote equivalent?
An MBA - not so much.
Then I went back to engineering as there's much more actual value in it and less politics.
There are a few things that I've realized make the difference between remote work and in person. When you are needing to talk to a team mate, working remotely you can just message them and get a response quickly, but this has the effect of interrupting them (or you), which can derail their train of thought. Sure, your still interrupting them when in person, but you can see that they are actively working on something and wait a minute or two for them to notice. They may also see you out of their pariferal vision, which alerts them without really interrupting them, so they can continue their thought before moving on to yours. It's possible to delay replying to a message, but for me personally this means I might take longer to reply to the message than I should because I forget to come back to it (also I swear Slack doesn't always play the notification sound).
The other thing I've noticed is that the lack of interruption can actually negatively affect me. Seeing others getting up for a break can trigger me to also take a break, which can prevent me from getting too lost down a tangent (or spending too much time on Reddit). Since it's in the preiphery though, this allows you to continue with your train of thought while still also being able to see it as a reminder. This allows you to better choose when (or if) to respond.
I think what message apps need, is to slowly fade in alerts, instead of harsh instant alerts. So you notice them, but aren't interrupted. This won't necessarily help with the tangent (or Reddit) problem, but it will help with the interruption of teammates.