His form may be a little too loose, but you definately don't want to have super strict no movement form. Heavy ass weight builds muscle plain and simple. A cross between the two is the best. My back blows up if I put a little english into the lift. When doing rows, the further you stretch your back, the more fiber gets recruited, thus more growth.
Some muscles like chest/shoulders need strict form yes, but not back. I'll pit myself against anyone in here who uses strict form on rows compaired to me slinging more weight/bigger stretch. (except for Apoc
) I use form that is in-between the two pictures.