Tip functionality is a business decision that comes from the top. The Devs have no say in whether a feature is included or not, and dislike it as much as you do.

With this little change, you might think you’re supplementing their minimum wage pay, but the owner can lower their pay to the “federal tipped minimum” in some states. You basically just make it cheaper for the owner in the long run (they’re probably sold on this by the Point Of Sale software company), and the workers can get little or no extra money.