DoorDash tips subsidize the company's delivery costs

DoorDash is a YC company (#8 by valuation as of October 2018) [0][1]. Could we get some insight here from people working with DoorDash?

[0] https://www.ycombinator.com/topcompanies

[1] https://en.m.wikipedia.org/wiki/DoorDash

tl;dr: DoorDash subtracts the "guaranteed" amount from the tip. So if the driver is promised $8 for the delivery and the customer tips $5 the driver makes $8. The tip went to DoorDash, not the driver. The way DoorDash words this kinda explains that's how it works so technically they aren't cheating drivers... but it sure is shady and outright lying to customers!

Tips are understood (and have a common-law definition) of being directly paid to those serving you. In some states a "house cut" of tips is against the law because scummy restaurants try to do the same thing DoorDash is doing.

By listing it as a "tip" in the app DoorDash is defrauding me as the customer.

Stuff like this seems to happen in tech all the time: they follow exactly the literal meaning of all the words in their terms of service, but the actual reality is the exact opposite of what the words imply.

Well, never using them again. That’s shady and there’s 7 other services that don’t do that (as far as I’m aware). I’ve tipped every time and have ordered probably 15 times in last 30 days

Do other gig economy delivery services do the same? This is surprising and seems to remove the incentive that a tip provides of doing an excellent job.

Only US still stick with tip. Why the customer need to pay extra money named as tip?