Theory of film critiquing

There is a certain talent for watching movies. Just the same as learning in school, watching films often enough builds an understanding of what works and what does not. Not everyone develops the eye, and that's where the difference lies. Like most anything, some people got it and some people don't.
One aspect of film critiquing that has bothered me for some time is the idea that a film is, 'good for what it is'. This is a cop-out. It is unfair to review a film based on other films of it's genre. Why? Because that puts the film in a box. Movies should be compared to all others. They should be compared to the art of filmmaking as a whole. To put that statement in perspective, let's say that (theoretically) someone could say Mama Mia is a good musical and give it a rating of 75%. At the same time, that same person could say Terminator Salvation is a basic action film and give it a rating of 60%. But if they had compared the overall quality against each other, Terminator Salvation is a superior film, just not as good in it's genre. You see what I mean? There is a point at which you simply cannot review a movie for 'what it is'. It is too irresponsible.
Another fault in film critiquing is trying to appease personal opinion. By saying, 'if you like action movies, you'll like this' is once again, irresponsible. There is a point at which personal taste and film quality cross. Think of it as an X and Y axis. There is a point at which opinion and quality meet. The area under which the two points meet is considered fair game for personal tastes. The area beyond where the two points meet is where tastes no longer can factor into the quality of the film. After that point, personal opinion is pointless because you simply can't review a movie based on what you like. For example, someone saying they think Jackie Brown sucked because it wasn't very action-packed. Well, that's not the point of Jackie Brown so what does it matter? If you are watching Jackie Brown expecting to see action, you obviously have a poor view of film.
I feel that the more and more I speak with people about film, the more frustrated I become. It's that these people don't understand what constitutes a good film. The same way I wouldn't try to compare Kanye West to Frank Sinatra because I know so little about what makes either great, people should not do the same with movies.