reminds of of something similar at fb with matt jacobson, who dresses well:

"And as one of the oldest and best-dressed executives at the company, he still looks completely out of place on Facebook’s campus. “I get stopped by security all the time because they think I am a visitor,” he said. “Security will come up to me, ask to see my visitor’s badge and say, ‘Who are you?’ ”"

Its not a good counter example because he’s got the social clout to break the rules - knowing when you can do that is also part of the unfairly unwritten rules.

If you start in tech on Monday, you’ll know by Tuesday what people wear and by next Friday you’ll probably have enough giveaways to never need to buy a t-shirt or hoodie again.

But they do care! If you wear a suit they'll think you're not technical like them. A big part of Google culture originally (when it was unusual) was wearing hoodies and jeans rather than chinos and shirts. If you didn't fit in with that you made yourself look like an outsider.

And the unfair bit is that it's not written down anywhere. You just have to implicitly know it. If you don't have family or friends in the industry you won't know it, they won't tell you, and so you won't fit in.

I've seen tech people scoff at people in suits, and look down at them. Have you never seen that?

Like the other poster mentioned about hardware vendors at Apple wearing suits, it’s probably not personal it’s just stereotypes at play. Google has a particular penchant for “watch out for tailgating” and expects all employees to challenge folks without badges. It’s not common to see other Google engineers in anything particularly formal, so it becomes a clear “hmm, I should make sure that person has a badge” or alternatively “hey security person, I don’t think they have a badge”.

I used to pretty much always wear the business casual "uniform" but a few years ago I found myself going a bit more casual at the more developer-oriented events I would attend because I was starting to feel overdressed.

If I showed up to a half-pipe in full wedding garb or to a wedding in skater garb, people would reasonably give me weird looks.

Being able to appropriately adapt to different situations is a needed life skill. “In matters of principle, stand like a rock; in matters of taste, swim with the current.” —Thomas Jefferson

The benefit I see in tech is you can wear whatever “weird” clothes you want and be accepted and given a chance to prove you can do the job much more than in most workplaces. Try showing up to a law firm or investment bank in flip flops and shorts vs showing up in a suit in tech. You’ll get a lot farther in the latter than the former. To me, that's fair (or at least wildly more fair.)

This usual ends up with some decent back and forth and inevitably I send them the following Oatmeal comic. [0]

My point is that if you play it right, you can turn awkward social norms to your advantage. You just have to be willing to ask.

[0] https://theoatmeal.com/pl/minor_differences5/suit