What we do know is that the full title includes “as the Gravest Crime against Humanity” and I can fully respect countries having reservations against that when there are other similarly horrible crimes. I don’t know why Germany abstained but I figure that some people might be pretty angry at them if they declared the slave trade was worse than the holocaust.

The “Gravest Crime against Humanity” part honestly explains why so many countries abstained.

The slave trade was an absolute atrocity and certainly one of the gravest crimes against humanity but should we label it as the gravest crime? Do we really need to introduce a ranking between slavery, the holocaust and dozens of other genocides instead of agreeing that they are/were all bad without picking one as the worst?

They‘re not supposed to make money. They are a non-profit foundation that takes donations to develop an open source project and I expect them to spend those donations on exactly that project and not much else.