It's not front-wheel locking that's problem, it's how it's applied
. Most beginners panic, grab both-brakes as hard as they can and end up locking both. Proper procedure is to apply both and gradually increase force
. Then as rear lifts due to weight-transfer, let up on rear (or leave it locked as trained in beginner crashes).
In vast majority of crashes where auto cuts in front of rider's path, there's LONG
skid-mark of rear locked-up tyre leading right into crash! If they had properly used front-brake
only, they would've stopped in plenty of time.
Imagine an invisible-hand pushing back on bike to decelerate. This braking-force is applied at tyre's contact patches. Due to C.o.G. of bike+rider system being higher than this force, weight-transfer towards front due to deceleration causes weight-transfer to front and tipping up of bike around front contact-patch.
The higher the deceleration-force (Bf), the higher the weight-transfer. Maximum
amount of braking-force is when 100% of weight is on front-tyre. This is when front-tyre has highest friction f=mu
. Similar to wings on F1 cars pressing more on tyres to increase traction. If Bf was lower to put rear-wheel back on ground, deceleration would be less.
Reducing braking-force in this case would have him miss turn and go off-road. Note no back brake used at all.
Even 12-yr old girl can do it!
The solution is improved braking-technique through lots of practice.