The Arab descent stuff is inspired by religion. Some European royals attempted to link their lineages to Ancient Hebrews. Just in the Muslim world this stuff got more extreme.
Majority of Somalis do not bleach their skin.
No it is not. Being lighter skinned is sometimes seen as a compliment. I never heard of looking like a complete foreigner being a big complement.
Fun fact, in traditional Somali culture it's only desirable for a woman to be light-skinned. It is the complete opposite with men. I realized this when some ayeeyo randomly told me I was dark and that that was good for a man. I asked what she meant and she said "Light men are girly and stupid." I then found out this was a common view in her day and it even popped in a history book that escapes me now.
Light skin was only favored in women which is actually a common theme across the world. Males are usually seen, subconsciously, as more attractive by their female equivalent in their ethnic group if they're darker. It's an actual documented psychological phenomenon worldwide that had physiological basis because in every human population, on average, the women are lighter/less pigmented. It's an actual known human sexual dymorphic trait. And people's tastes over the millennia have been influenced by it. Hence the recurring theme of the fair maiden and the tall, dark and handsome man.
Cadaan women were well placed to capitalize on this in the modern era and some sad and pathetic men do coon for light skin like they wanna be Brad Pitt. That is sadly a thing but clearly just a result of recent western influences. A Somali dude from century ago would never think to be lighter as it was seen as being girly and weak.