It's hard to maintain open source software that needs infrastructure. Everyone is a volunteer and it's not like the Mandriva project has the resources to fully vet people as well as have a high quality RBAC and access control system. This guy sounds like maintained a large project, offered to help, and Mandriva saw the Trojan horse as a way to alleviate a lot of their problems.

And it didn't sound like he was able to "nuke everything" - it sounds like he had access to their repository infrastructure (which is reasonable given he was volunteering to host it) and then lashed out.

If anything, I think it's a bigger organizational red flag that they agreed to privately host their source code on some random git forge and not a larger, more communal one. I mean, even if they didn't want to use GitHub (did this even cost money for them) then there are other providers to choose from.

It just sounds like the Mandriva maintainers are trusting and good folk who may be overworked running an open source project and that led to a bad apple entering the bunch. It's hard for me to be mad in that kind of situation.