Wild speculation based on "I think it sounds like that" isn't actually constructive.
I've had the blog post updated to say "allied with" rather than "joining the family of" in the hopes that people will actually read the words going forwards rather than jumping to conclusions.
As it stands, the blog post just isn't very transparent. It mentions PIA "provid[ing] us with opportunities and resources going forward, including an operating budget", and that it is "now officially part of the PIA family".
So you have money changing hands, and property changing hands. That doesn't sound like a sale, it's what it is.
Unfortunately, it's rather thin on substance regarding future intentions. But I guess it could indeed make sense purely as a pro-bono project with a bit of a PR windfall for PIA.
I completely agree. The former doesn't generally result in a press release and/or public announcement that includes phrases such as "... will continue to operate as a not-for-profit entity under the same management, with the same principles, ...".
Personally, I don't care one way or the other whether this was a "purchase" or a "merger" or "alliance" or whatever you want to call it. I have been a freenode user (and, if memory serves, an "occasional financial supporter") since (probably) shortly after it became freenode and I expect that I will continue to be a freenode user in the future (unless something major happens to change that).
Vaguely worded announcements and a lack of detail, however, tend to cause things like "wild speculation" and "jumping to conclusions".