Not about diversity, just an example of culture. I wanted to pick a counter-example that didn't include pizza or alcohol, and "chocolate brownie" came to mind first because I had one in front of me. (Unfortunately not company sponsored. It's long gone now!)
The general idea is it's good to know the perks that are offered. Somebody will always feel left out. (People whose diets preclude brownies, for example.) It's good to know what the culture is going in, so that we can self select and only choose to work for places in alignment with our beliefs.
Perhaps more useful signals of culture would be hours worked, amount of autonomy versus teamwork, and types of customer interaction.