You're backing your argument based on a non canon source? Seriously?
Sure, why not? Made by Capcom, right? May not be a 100% best source, but certain elements are definitely salvageable, such as Zero calling Roll a Housekeeping Reploid because he just can't tell the difference, thus proving that in the 21XX world, Classic series robots would still be considered Reploids since they are also sentient androids, very similar to Reploids, simply set aback by inferior technology and mental capacity. (they sure as hell are not mechaniloids, right?)
Rock does not explicitly hurt Dr. Wily, but attacks the machine that Wily is inside, without harming him.
Irrelevant.
"1. A robot may not injure a human being or, through inaction, allow a human being to come to harm."
Rock directly attacks a machine with Wily inside, causing it to explode. There is GREAT risk of Wily being seriously hurt. I wouldn't quite expect you to be fine after YOUR car blows up with you inside, no? Rock, far back in 1, had no way of knowing if Wily could or could not be injured by his machine's destruction.
And I mean, come on. You are attacking his machines with such things as tossed Sawblades, concussive explosives, and even miniature black holes. You cant seriously tell me There is absolutely no risk for him to get hurt, especially when you always attack the COCKPIT where he is seated once the initial Skull facade is broken.
And Wily DOES get hurt by it. Comedic value aside, he ALWAYS ends up scuffed, bruised, clothes torn, and sometimes missing a tooth or two.
He never kills Wily, let alone directly; not even in MM7, where in the Japanese version he obediently followed the First Rule of Robotics.
Of course he would not kill Wily. You dont need the 3 rules to keep Rock from killing people. He knows it's wrong. He fights for justice and peace. When Wily, taken aback by Rock's sudden lapse of moral judgement, questioned it, Rock didn't say anything. he just stood there, most likely realizing it was wrong. Dont underestimate his sense of Justice. The same sense of Justice that had him volunteer to be converted into a battle robot to stop his rampant brother robots.
Also, there is this:
"2. A robot must obey the orders given to it by human beings, except where such orders would conflict with the First Law."
Rock would have to obey every order given to him by Wily. He would have to obey if Wily told him to stand down.
Asimovian Robots do not good battle robots make.
EDIT: the 0th law would also cause a paradox for Rock. It states that a Robot may not harm Humanity, or by inaction, allow it to come to harm.
so yes, that means he would have tofight against Wily to protect Humanity, since Wily can cause damages and harm people.
BUT, by attacking Wily and going against him, a Human, he would be breaking the first law, where he cannot allow Wily to be harmed or come to harm. he would also be breaking the second law, where he must obey any orders given him by a Human. And naturally, Any order Wily gives him would also break the first 2 laws, or the third even, if he were to order Mega Man to terminate himself.