[legion]

It's very simple.

If the FIA has any excuse to penalize McLaren, they exact the most severe penalty they can think of without exception. (Like a $100 million fine, or an after-the-fact time penalty when a there was plenty of time to give a stop-and-go, or excluding them from a race for something that all teams do.)

If Ferrari does something, first they will try not to penalize them or shift the blame to the other team involved in the incident. If the incident is egregiously Ferrari's fault, then they will try to apply the least severe penaly possible, even when it breaks the FIA's own rules to do so. (Like give a small fine when the rules clearly call for a time penalty, or penalizing the car that had the right-of-way in the pits.)