Because it is a bit politically charged and with that, by doing upon a personal blog the company always has that plausible deniability excuse and from a business aspect - this is best way as affords best of both Worlds. If it goes well, good, if there is a twitter rabble mob, then as not company domain - the good old - nothing to do with the company and the rouge individual excuse can be plausibly played.

It's a smart move, though you do see thru it all over the years.