Why are minorities cheap?

I never quite understood why American minorities tip so poorly?

Most of the time you have people of Latin or Black (African American) decent come into a restaurant and question prices on your menu. Most of the time menus are posted outside.

The other day I had a party of 5 come in, look at a menu ask for take-out...fine! They realize it it was a burger discount day and ask for To-Go. Once told it was dine-in only they stayed, Gave a 10% tip.

I don't think they understand that the servers make $2.63 per hour.

Today, a party of 8 including children came in and ordered burgers and steak tips  as well as alcoholic drinks. They stated that our menu was a bit higher in price (over heard by the server and myself) and yet ordered what they did. They were needy as well and ordered pricey drinks. Their bill was about $110 and left $9 for a tip.

That basically translates to : We spent too much on food and drinks we will figure out what isnt Too much to leave as a tip.

It becomes fustrating because this creates stereotypes.

To bring it home: my aunt likes to send food back that may not taste like her own or cause scenes for reservations not ready for when she makes them. She basically expects free food is what it is.

These people have never worked in a restaurant and should never eat outside of their own home.