Yes. That is his real justification.
In 3 years of allowing concealed weapons, Kansas CCW holders have failed to shoot people over parking spaces and fender benders (that's according to Josh's own data, to which he contests that the real numbers have to be higher). Therefore, Josh Sugarmann thinks it's too early to call Kansas CCW a success. But as soon as a CCW holder shoots someone (and it will eventually happen due to the "law of averages"), I have no reason to believe Josh Sugarmann won't think it's too early to declare CCW a failure. Or as Josh succinctly puts it, "... past performance is not necessarily indicative of future results."
And that is why his logic is truly baffling, if there is even logic to be found here. It's akin to saying, "It's too early to call the fire department a success because it's only a matter of time until a fireman commits arson."
Josh Sugarmann's "score keeping" (with rather low scores relative to the total number of CCW holders) is nothing more than another one his many attempts to attack the lawful possession and carrying of firearms.
Despite Josh Sugarmann's attacks, in the entire history of CCW, not a single state has so much as pondered legislation to repeal their CCW laws. That's because crimes committed by CCW holders, such as the ones Sugarmann documents, are extreme rarities. Statistically irrelevant and non-issue.