> Why do they make less than the minimum wage? Why do laws allow it? Why are they treated as a "special case" instead of just having a set wage like all the other professions?

It probably has something to do with history or tradition - around the tipping model in the US.

Basically it was the case (and still is generally) that if you did your job exceptionally well, and made the customer feel genuinely that you did an exceptional job at handling their needs and wants, they would tip you - and in many cases, the tip would be very favorable.

This worked great if you were the one getting the tip directly; if you were so lucky and so skilled, you could easily make much more than what you would have gotten as a "fair wage" (indeed - for example for bartending you can make a lot of money as I understand it).

This doesn't work well, though, in cases where you have to do tip sharing - because then you, as an exceptional service provider, are now potentially supplementing others who give average or even sub-par performance (though it can be favorable if everyone was doing exceptionally well - but this is rarely the case).

It also doesn't work well if you have customers not upholding their end - ie, tipping appropriately for the level and value of the service they receive.

I personally adhere to a tip rate of 20% for standard service; if you do better, you get more, if you do worse, you get less (but I tend not to go below 10% - unless you really deserve it). However, I'm increasingly seeing myself as being an outlier; many people either tip poorly, or not at all.