I think what he is talking about is bleeding edge for China. Sure, J-31 looks like F-35, but it's not like SAC expects to get any help or can subcontract American companies to produce any subsystems. SAC would have to find domestic partners for all the subsystems on the J-31. Since china has not developed a mature gen-5 fighter infrastructure, this would be bleeding edge for China. I think that's what he meant.
Oh BTW, develop of a 5th gen fighter sounds so easy to you. "Just put something together. Boom! You get a 5th gen fighter". If it was that easy, everyone would have done it. It is a complex and sophisticated and needs highly coordinated effort from multiple institutions and decades of hard work.
exactly right!