They're not "advertising a very different commercial product". They're recommending you actually use a maintained alternative. Bitlocker is probably the most viable alternative on Windows.
It's also possible that Bitlocker solved the problem well enough for them so they saw no gain in maintain TC any further.
How would a software with closed source from a company that has been gladly working with the US government in the past be a "viable alternative" to TrueCrypt? Really, please try to read the comments above before you enter the discussion.
BitLocker lacks another one of TrueCrypt's most important features: open-source code, readable, verifiable, and compilable by any interested user. BitLocker is almost definitely already backdoored, so encouraging people to switch to that makes all of that data accessible by the powers that be.
I think it's silly to pretend like no authorities would have an interest in promoting the use of closed-source encryption techs. Apple and Microsoft were both willful participants in the PRISM program. TrueCrypt was the only open-source FDE software that had widespread adoption on non-Linux systems. After this, no major corporation or group is going to use TrueCrypt to encrypt anything anymore and will rely entirely on the backdoored encryption solutions provided by the NSA's known and confirmed compatriots.
As I said even if not recently they still invested many years into that project.
Of course it is juvenile to senselessly ruin the code and suddenly advertising a very different commercial product, especially without proper scientific reason.
Not to mention that precisely because they haven't done much work lately I don't see any reason why the developers would disfigure their project like that.