Linux started out as a hobby project that widened the schism in the Unix world. Yet things turned out fine
Why? There are multiple kernel versons with different support. Android had and might still have their own kernel version, and I didn't notice anything bad. It's just another Unix implication.
I have trouble not reading this as "forks are bad", which seems to be missing the point of libre software a bit. Am I missing some nuance lost in the brevity of two sentences?
Forks are not inherently good or bad but can seriously muck up an ecosystem if they are not well-justified. Mucking up the Linux ecosystem would be BAD.