Where did you see that governments in particular are buying up Bitcoin? I don't think I've seen a single example of any major government buying up anything more than a nominal amount of BTC.
Most major governments, with the US in particular, already have large troves of Bitcoin that are seized from criminals. For instance, I think I recall the US seized 100,000 BTC from the operators of Silkroad.
I doubt they need any more than that.
I agree that it sounds like a conspiracy thing. There are some govs, though, that are believed to have a lot of bitcoins, right? There are some articles about it on Investopedia. According to
this article, Bulgaria has 200k BTC, North Korea definitely has quite some (but since it's North Korea, there's no detailed information), whereas according to
this article, the US government at least used to have $1billion worth of coins. But all of these things are more or less official, known from the auctions of the seized property (like the one you've mentioned with Silkroad), and it's not something that became more active recently, so I think the op might be wrong.