When you land you tend to go out the front rather than the back for weight back is good.

You pretty much never land in perfect alignment and even it you do you get pushed around.

If you land front wheel first the rear wheel is going to come around and only get worse. When the rear does touch it will be out of alignment.

Rear wheel first the font is pulled into alignment and front steers so the front (can be) in alignment when it touches even if the bike is not yet in alignment.

Also legs are longer and stronger than arms to absorb the shock and can stay in position on the bike.

Absorb with arms brings you forwards and that is not what you want in a front wheel landing.

When you land you tend to go out the front rather than the back.

You pretty much never land in perfect alignment and even if you do you get pushed around.

If you land front wheel first the rear wheel is going to come around and only get worse. When the rear does touch it will be out of alignment. As you absorb with your arms you only get more forward and go out the front. If you extend your arms and put you weight back as far as you can you have to take the whole hit. Your body is not in a position to help absorb the landing.

Rear wheel first the font is pulled into alignment and front steers so the front (can be) in alignment when the wheel touches even if the bike is not yet in alignment. Also legs are longer and stronger than arms to absorb the shock and can stay in position on the bike. Even if you are way rear wheel early you can shift weight forward and your body is in a position to absorb the landing.