Your point 2, nowhere in the rules does it say its for off the ball contact.
You are right , its talking about fouls for which free kicks and penalties are given but it's not talking about tackling. I'm not sure where the specific rule is for tackling and challenging for the ball but what I do know is that its perfectly legal to tackle a player and get the ball , and if in the process of doing so you make contact with someone
and impede a players progress then it's not a foul.
This happens every week when you watch football. Someone slides in or sticks out a leg and gets the ball and the attacker is impeded , knocked over or trips over his legs etc etc. When this happens the ref does not call for a foul unless it is reckless , dangerous or shows a lack of care for the opponents safety. Obviously that's because tackling a player is exempt from being a foul (unless it's dangerous). You cannot impede a players progress unless you are winning the ball (or making contact with) in some way. Which part of this is a problem for you? Please explain what you see on the pitch every week.
But like all discussions on this forum you won't accept anything but your own opinion.
The rules of football are not my opinion. The rules do not care about my opinion or yours. They are what they are. What I will not accept is something that's not logical. If you told me that if a player head butts another player then he shouldn't be sent off then is that my opinion versus yours? No , of course not. You argument is with the rules of the game , not with my "opinion". Please try to understand this.
You think it wasn't a penalty and wont even tolerate any discussion contrary even when the rules are posted,
But you completely misunderstood the rules and when they apply and don't apply. It's no good just posting rules without understanding their exemptions. For example , there is a rule that says you should not handle the ball , yes ? But does that mean when a player is doing a throw in its handball? No. Because that rule is not applicable to throw ins , just like the normal rules of fouling take on a different meaning when tackling the ball.
I can see why it was given, the rules are a bit vague, we won, move on.
I can see why it was given too , but not for the same reasons as you. I think the ref just didn't see Gueye's contact on the ball , it was just too fast and too slight for him. In full speed I might have given it too. If he had had access to VAR though he would have overturned it after seeing the touch from Gueye. You think the ref saw everything and gave it anyway. I do not.
I think the rules have grey areas when it comes to what is dangerous play or not. Some refs will tolerate more physical contact than others (eg premier league versus CL) , but when it comes to winning the ball without endangering an opponent the rules are quite clear really.
I would agree that Gueye's tackle doesn't look quite right and that it seems a bit unfair that he can stick out a leg , get a slight touch on the ball and in doing so put Martial on his bum in the penalty area. I get it that it doesn't look right somehow. However , whatever it looks like to any of us is yet again irrelevant because he's not done anything that the rules say he can't. He's allowed to challenge for the ball in that way as long as he makes contact with the ball before the player and it's not dangerous. The rules do not care about what we think or feel about that.