https://www.dol.gov/agencies/whd/state/minimum-wage/tipped

And I've also worked in a restaurant before. They are correct.

Or they could have been kitchen-staff. They are one of the biggest victims of tipping culture.

Essentially chefs are generally paid much, much less than wait-staff and it is very difficult to correct this balance. The reason is that in a normal business you would raise prices to afford to pay higher salaries, but since tips are percentage based this also raises the wages of wait-staff. This becomes a bigger and bigger issue the higher the tipping percentage goes. Restaurant margins tend to be razor thin as well, so raising prices would be the only way to raise kitchen-staff wages.

It's one reason why many restaurants are struggling to find kitchen-staff, because even highly trained chefs can make 2-3 times as much working front-of-house. There are quite a few restaurants which are trying to fix this by banning tips, but it's difficult due to resistance from customers and wait-staff.

You guessed wrong. I have a strong opinion against tipping specifically because of working in restaurants including as a server.

I did not like the inconsistent pay and would have preferred consistent pay. I'm sorry if that doesn't align with your worldview.