He is rounding a lot and it is shit form, nothing else. It's a massive lift, he is roided up, so no one cares.
It is not a rounding the upper back, his whole back looks like a bamboo crane.
He does know what he is doing, and i'm sure that he'd acknowledge the form issues if you'd ask him but it is simply stupid to say his form is good. A non steroid using beginner will have a much higher likelihood of sustaining injury if he lifts like Larry.
That does not take away anything from his achievments. The guy ist insanely strong, and watching videos like this does motivate me and hypes me up before training. He just isn't a poster boy for correct technique, that's all.