I don't have a problem with them releasing them, but it being a recessive gene and not really that helpful without human intervention it will probably die out again.
If they want to be bred in captivity and seen there - that is one thing but reintroducing them? Because of the color they have a huge disadvantage because they are highly visible - that isn't really a gene you want being passed on as cubs that are born in the wild all white are more likely to be killed at a young age because of their visibility.
So actually... I guess I do have a problem with them being produced for an aesthetic reason since it is a disadvantage to the lion.