Without speaking on the GP's behalf, perhaps the leverage in a particular strategy represented by investing directly in the company made the risk worthwhile whereas the more diversified, risk-averse but lower-leverage investment represented by BRK/B was not?
Yah, basically, what I did was buy more of the competing companies, even though I didn't think they were as as well positioned. Turned out to be a fine investment, better than the BRK would have been.