It's a topic for a different thread, but I guess Tohei had been practicing a lot since his run in with Herman two years earlier.
Back squarely on topic, and equally interesting to the points that Chris and David highlighted:
Why did Tohei resort to a "judo-like" leg sweep in this encounter?
Nothing against leg sweeps, but why did Tohei not
use one of the recognizable techniques of aikido, that I assume he learned from Morihei Ueshiba and had diligently trained in for around 20 years?
I would propose that the answer is in Osensei's complaint - "There's no need to throw someone who isn't attacking you!"
In other words, and this is how I am understanding this thread, Aikido strategy and tactics are not directly relatable to these kind of match-like/stand-offs often seen in "dojo" settings and that is widely through the commerce of martial arts becoming widely accepted as "real," but is rather more directly applicable to moments of actual human-vs-human violence - the kind were life and not trophies and titles are on the line, the kind where someone is looking at jail time, the kind where multiple lives (including the lives of folks not even present) are ruined.