I feel like people complaining about this didn't grow up in the IRC/IM era. It probably depends on your corp's culture as well, but for us, Slack is a very informal communcation mechanism. If you need to write something formal, you use an email. Slack is equivalent to shouting out to the room (as if you were there in person).
I definitely grew up in the IRC/IM era and continue to run one of the larger IRC networks in the world... But people using proper sentence structure and 'all in one' messages are often the people you want to talk to.
There are some people who basically braindump many lines of text with no punctuation but they are not the most common and it's a signal that the person does not respect the room- so they are somewhat scorned even if not directly.
I think it's less about formalism than it is about clear communication.
People will also be confused if you shout out a message to the room without appropriate pauses (commas or periods) or without the right tone (question marks).
But that's the thing, if you ever used IM for a significant amount of time, you know you don't need punctuation. Question marks, yes, he's right about that.. but I certainly don't add periods at the end of every five word chat post. Maybe if you're writing a paragraph in Slack go for it, but if I have a few sentences to say I'll usually just send them in a few messages instead. This whole idea of writing formal multi-sentence messages in Slack shows the author's dissonance with how real-time-chat is supposed to work (keeping in mind that Slack is supposed to be next-generation-corp-IRC).
And how is real-time chat “supposed to” work? It presents a text box to type into. The text that I type in there is proper English, with correct punctuation and sentence structure. I don’t see how it being real-time suddenly means you need to abandon that.
In the same way, face to face communication doesn’t suddenly abandon inflection or tone simply because it is real-time.
And again, I think it comes down to culture. In your workplace, you're in a room with your coworkers: do you ask "Excuse me everyone, could I have a moment of your time? Does anyone know the status on the internal project Crusade Against Initialisms? Thanks in advance!" or do you say "yo what's the latest on CAI?". In our org, Slack is the same as talking in person (since we, you know, can't do that anymore thanks to WFH and whatnot).
I don't think it's so much a corporate culture thing as a context thing. There are certainly channels in my work Slack that I feel compelled to add more kindness phrases to when engaging.
Following your metaphor: if I were in a room with a couple hundred other people I _probably would_ say "excuse me" before shouting a question.
In both instances they disturb the train of thought which is why I am not a huge fan of open plan offices, nor instant messaging during coding and concentrating. It’s why libraries don’t have buzzers and bells going off.
> I feel like people complaining about this didn't grow up in the IRC/IM era.
At one time most written language didn't put spaces between words (some still do), and many languages don't write vowels. That's not a good reason for doing the same in your informal English Slack messages.
You can write an informal message and still use punctuation.