Erm, isn't "share-alike" closer to the GPL than MIT/BSD licenses? That is, the whole point of the GPL is that anybody who uses your code has to release the prod

Erm, isn't "share-alike" closer to the GPL than MIT/BSD licenses? That is, the whole point of the GPL is that anybody who uses your code has to release the product under the same license; this is exactly what the "share-alike" licenses do as well.