Marquez was very much racing (and not only racing, but racing a la Marquez, and not only racing a la Marquez, but racing 150% a la Marquez) for his position vs Rossi, or better yet, to make sure their two bikes/bodies distance would never be more than 10 centimetres. And did not apply the same treatment (being eufemistic, since he actually never even tried) to Jorge. So he deliberately chose which one of the two title contenders to favour.
Was it clear? So clear that if you deny it you're just as biased as a Rossi fanboy who would keep his face straight while trying to say that Rossi didn't kick Mm on purpose
Was it in his racing rights to favour Lorenzo? Yes. Which makes it even funnier that a lot of people in this forum don't admit it.
Why would he do that? Assen, of course.
There's race laws, and there's life/race ethics. Of course, in order to decide who the final champion must be, only the first ones have to matter. But as spectators or supporters bringing them both into the table, as opposed to only one of the two, is merely an exercise of realism.
What Valentino did was at the same time against the rules AND understandable IMO. He was about (maybe, who knows, he is still about) to make history, until a spanish little nuthead with an incredible career still in front of him decides to start play borderline games with him in the last two/three races. This still doesn't justify Rossi, which has strong probabilities of RIGHTFULLY (again: rightfully) losing the tenth cause of his kick move.