Jason Statham's whole argument is ridiculous. OF COURSE they use CGI, green screen and stunt doubles. You can't create the world from which the Avengers hail with makeup and good acting alone. How menacing would the Hulk be if it was just Mark Rufflo painted green? How frightening would the aliens and bad guys be if it was a bunch of guys in prosthetic makeup pieces? How cool would Robert Downey Jr. look in a literal metal suit that would be too hard for him to walk in? CGI and SFX aid in the movie's story telling and make the impossible things within the story become more tangible to the audience. And as for stunts, I pretty sure the entirety of the cast of any Marvel movie does their own stunts until the producers deem it too dangerous. And while Marvel is creating box office smashes, Statham is grinding out basically the same movie over and over again. I would love to see him try and actually emote and do a scene which he can't just shoot someone or blow something up. When he can do a dramatic, deep, and meaningful scene then kick a bunch of alien asses without being completely plastic, then he can talk trash on the Avengers or Marvel in general. Until that time, in my eyes, he is just a one trick pony with no concept on what it means to be an emoting, and deep actor.
Besides, he was probably just pissed because the Avengers movies make much more most of his do. (With exception of Fast 7, but that was because of everyone else that was in it and for the late Paul Walker.)