I think both points of view have some merit here.
1) all fouls get treated the same or 2) some leeway early doors to manage the game
1) is more logical & easier to argue but I still go with 2) because imposing the laws & management of the game are NOT exactly the same thing & I think that game management is more important than total accuracy where it isn't absolutely essential - it's also worth pointing out that a very decent % of incidents for yellow cards for example are a matter of opinion. For instance, the Madrid guy is slightly pushed before, I think, his first tackle which doesn't have a lot to it anyway. Ramsey looked like he played the ball to me, no one got hurt, not a card for me either. But based on earlier, Madrid are not getting a fair deal here, if I say that. Other people think it's a yellow card anyway, even if he did get the ball.
I would just try & be fair but in doing that my early decisions (probably leniency, possibly technically wrong even) will affect later ones.
Let's say there's a 1st minute 50/50 penalty - that I can reasonably give or not give. Either that sets my standard for later penalties or it doesn't because I am 100 % consistent - but I don't think I am. I give you the penalty, I probably don't give you the 2nd soft one later but am a bit more generous to the opposition on their claim so that things 'even out' - I'm trying to be fair. More likely, I don't give it & in game management terms I have more options, Arsenal can have the next one, I've set my standard for what constitutes a pen and I can disallow a later Madrid possible pen with a clear conscience because I've been fair. And most important, I haven't committed myself & closed off these options in the first minute.
My argument for this is harder than the one the other way around but I give you a better game of football with this approach more often than applying the letter of the law before I have to. Refereeing is not an exact science I'm afraid.