I don't buy that. I think Hasbro is just trying to shoe horn it in for marketing purposes - I don't think Hasbro's marketing or it's more administrative departments fully understand their own brands beyond the commercial aspects. The developers who are the people who created the game have said that War for Cybertron is G1 and when you play the game, everything points to that.
It may not be exactly within any pre-existing G1 continuity like Sunbow, Marvel, DW or IDW but it is certainly within it's own take on a 'pre-Earth' G1 continuity.