That's just false my friend. Rear tires are critical to keep you going in the right direction, even in the FWD cars, let alone the 4wd/AWD setups.Power is useless without control.
Also the front wears faster because of the weight of the drivetrain over them and the fact that it steers and has power going to it.
This is a common misconception that fronts should get the best tread when you can only replace two tires.
Here is one reference I found in my quick search but please do your own research and share any reliable sources that claim that the fronts should get new tires instead of rear.
Tire Replacement Guide - When & How to Replace Tires
Tire Replacement Guide - When & How to Replace Tires
Here's another one:
6 Tire Myths Debunked
PM contributor Mac Demere, who worked at one of the big tire companies for years, corrects a few commonly held misconceptions you might have about your tires.