A bit rich from Microsoft to talk about hoarding when the patches they released over the weekend were all signed back in February... i.e. they are hoarding fixes to their own shit for their $$$ extended support agreements.
source: https://arstechnica.co.uk/security/2017/05/wcry-microsoft-is...
So I don't really know what you mean by 'hoarding the fix'. The patch was not initially released to some OS versions because they are NO LONGER supported.