I would be interested in seeing the argument of someone who is not part of "HN, Reddit, and Slashdot" against the proposition that cryptographic software that only few people have access to the source of is not trustworthy. I do not claim being involved particularly deeply in either the academic or the industrial security community, but my impression from the occasional academic discussion group I have managed to find the time to drop in on always was that this and/or some related proposition was part of what is commonly held to be true beyond the need for argument.

Regardless, there are two separate questions here - firstly, whether some sort of foul play actually was involved with the Truecrypt project closing up shop, and secondly, whether the recommendation to switch to Bitlocker should be considered sound or not. I believe that the recommendation is dangerous regardless of what happened with Truecrypt - at the very least, making no recommendation at all or telling people to stay with Truecrypt (7.1) for the time being and giving the OSS community some time to try and fill the vacuum is not worse than making said recommendation under any circumstances. In that light, even if your scenario is more compelling, I would argue that simply to err on the side of caution, one ought to refrain from pushing a narrative to the effect of "nothing fishy here; these perfectly trustworthy people just told you to use Bitlocker, make of that what you will" at this point in time.