While the article makes a good point and I agree you should never assume anything. I find it funny that he does not touch on the fact the he himself assumed Donny would not kill him. He assumed his attacker would be of a sport match mindset. While warning us about assumptions, he made and hedged his bets on his very own.
Believe that's what the article was about if you want, but I think the point is that there are always assumptions and it is better to be aware of them.
I assume the "he" above means Takamura not Threadgill. I think it is interesting that you are assuming what Tak's assumptions were. We don't know what Tak held in his mind, but given my distant impression of the man, Donny had no idea who he was playing with or what field he was playing on.
And isn't that the essence of winning? "If you know your enemies and know yourself, you will not be imperiled in a hundred battles." Sun Tsu