Earlier quoted context omitted.
Startups define different classes of stock. The class A shareholders are the founders and investors. Everyone else gets class B shares. The A class shares don't get diluted, and they are inherently worth more anyway.
This is not standard. Normally founders and employees get common stock and investors get preferred stock. Founders may get more stock issued in a round, and VCs/founders can pretty much rework the cap table to their liking if they really want to. The difference in return between founders and employees is down to percentages. Founders get 25-75% where employees get 0.01-1%, maybe a bit more if they're lucky.
So that's a scam by the founders to the employees, in my book. It's fine, it's just that I am not sure young professionals joining a startup know that.
Said differently, if you join a startup, you should not work too much without compensation, and you should not care about making it super valuable, because you don't benefit from it. If you have a super good idea or realise you have expertise that would make the startup valuable, you should leave and become a founder yourself.