My naive guess is that it's a null hypothesis situation. You not seeing a problem isn't a useful indicator for if there is a problem. More than that, it probably hits too close to home for mostly software devs, with the dreaded "Well it works on my machine."
Must be something like that. More than anything, I'd love to know why Firefox seems to be winning on this page; practically the opposite of what you'd expect out of Google pages (because, even without a tinfoil hat on, it's clear they don't test on Firefox often). Maybe uBlock Origin is just cutting out some poorly-written script, who knows.