Anecdotically, to this date and after 4 workplaces (FAANG included), I am yet to see what a bro culture is.
To my eyes and experience over 10 years interacting with people, I have seen nothing of the sort, for which I believe this kind of culture must be very conditioned to the right (or wrong?) mix of individuals that by far do not make justice to the average SV engineer.
I've seen it, and to be honest I've only seen it in the ranks to the exec team rather than the tech team in both FAANG and startups.
The tech teams and tech managers are usually trying to impress you about how they spent the weekend coding on a PDP-11, playing board games or mountain biking while drinking custom brand protein drinks. Generally harmless stuff like that.
The exec teams are where the sociopaths live and work, and I've seen all sorts of bro one-upmanship there. The worse types, by far, are the rugby bros. The tales these guys tell each other are always of the "here's a horrible thing I did, so don't mess with me".
To my eyes and experience over 10 years interacting with people, I have seen nothing of the sort, for which I believe this kind of culture must be very conditioned to the right (or wrong?) mix of individuals that by far do not make justice to the average SV engineer.