Or a University who doesn't want to get sued / get bad publicity for screwing with a tool used by government agencies...

It's possible, but I think that's the paranoid / Hollywood spy version of this. Not saying that this sort of thing doesn't happen - the spy agencies take themselves very seriously but aren't big on effective policies anyway, but unless there's a specific operation that is relying on this specific exploit, and someone in the government got advance details of the nature of the exploit, it doesn't seem to have a particularly high prior probability. Anyone with a significant budget can probably pay for any number of zero days so they don't have a single weak point like "if anyone fixes this bug in the software our operation / malware will stop working".

Generally when you see some outside force trying to suppress security research and the presentation thereof, it comes from the companies who will actually have to fix the problems and deal with support calls (or companies who feel that security through obscurity is sufficient and are hoping to somehow suppress the information from ever getting out). In this case, that would be maybe the Tor Project, but they generally are very receptive to this kind of thing.