Forks often arise from differences of opinion in the direction of a project. And tokens are increasingly a mechanism for voting on changes to their protocols. Since the point of a fork is to try a new path, the new fork may not want to port all of the prior holders opposed to trying the new path the fork was created to take.

I think the whole narrative of blockchain without bitcoin will amount to very little.

Redistributing tokens is a balancing act. In most cases, forks probably want to keep ownership for users constant so users have at least the same incentives to use the new fork as the historical one.

Fred Ehrsam Quotes