You can also ponder it from the perspective of a rational hijacker. Why fake BFO when you could have just had no pings at all?
If this was the goal, then it was achieved admirably - a mystery was provided, and the press took the bait, and largely ignored the brewing unrest in Ukraine.
In terms of the plausibility of his theory... it's plausible. It doesn't mean it's right, but it's plausible. I've been to Baikonur, and it's in the middle of absolutely nothing, has very, very high (Russian) security, and is a pretty ideal place to disappear anything.
The one thing I think he does get wrong is that he thinks building demolition in freezing temperatures is weird. This becomes a hell of a lot less weird when you realise that in the summer, temperatures there reach 50+ Celsius, and doing outdoor work in the dry cold is vastly preferable to doing it under the blazing sun.
It becomes even less weird when you consider that Baikonur is being edged towards end-of-life, as Russia are building their new cosmodrome at Vostochny.
Making an aircraft disappear might have taken Ukraine off a few front pages, but the propaganda benefit to Russia was - as any reasonable person would have anticipated - minimal at best. It made essentially no difference to Western policy towards Russia, and if anything drew a bit more attention towards crashes involving Malaysian Airlines 777s than was good for Russian interests.
Conversely, the implications of being caught hijacking an aircraft full of civilians and flying it into their own airspace would have been very severe indeed, especially given the number of citizens of their neighbour and only major international ally on board.
Consider the reward is minimal at best, the cost of failure is exceptionally high, and the probability of failing to hijack and fly an aircraft several thousand miles over multiple jurisdictions without detection is comfortably above zero.
Assume that anyone with the acumen to pull this sort of stunt off successfully possesses the faculties to do some basic weighing up of risk and reward an ask yourself why on earth would they do something so risky for such a trivially achieved and insignificant objective as distracting news media
Just because a particular organization theoretically could pull off a particular course of action doesn't mean it's not ridiculous in the extreme to assume they would.
I think this is something that can often backfire. If someone creates evidence that say's the plane crashed at location x, when location X is searched and there is no plane, I still have more information than I started. I know the evidence that led me to location x is incorrect. This could be because the data is bad, or due to tampering. If I'm now focused on tampering and able to corroborate that it is tampered with, I now have a new area to narrow my investigation, based on who has the skills, ability, and motives to tamper with that data.
Now, I would agree, if the goal was to create a short term disruption to the investigation, which didn't require holding up to scrutiny in the long run.
Because this is where you can bury your evidence real deep.