Nobody uses single-game +/- anymore, and any knowledgeable fan would never use unadjusted +/-, regardless, same with offensive or defensive rating for an individual(probably the most misused stats in the basketball realm, the same number that has had Carlos Boozer as an elite defender, etc)..advanced +/- metrics are unquestionably useful in both the individual and team unit setting, and just like with any good stat, it should be used in conjunction with other metrics and common sense, of course(which is something anti-stats people always ignore in their criticisms of the numbers, they always act like stat people are basing an entire argument on 1 metric)..
OP's point is silly, but it's mostly agenda-driven..he constantly moves the goal posts in the way that he evaluates players..the reason he hates +/- numbers is because they are very kind to players he dislikes on the Spurs(Kawhi, specifically, and DG, as well)..he was the biggest Splitter hater on this forum, too, and pro-Splitter posters would use metrics to display his on-court impact

..that's the primary reason, but the actual thread itself was created after one of his favorites(Jimmer) had a poor game, and I'm assuming people were citing his individual game +/-..