Why not? "Quality" is both objective and subjective. If someone tells you they enjoy a piece of beef from McDonalds more than a cut of filet mignon from a five star restaurant, then obviously that is their prerogative. But objectively speaking, that cut of filet IS a higher quality serving of beef no matter what anyone tells you. More care went into it's preparation, it's made up of finer ingredients, and it's more tender. Now if none of that matters to you and you'd still rather opt for the McDonalds hamburger because you can't really taste the difference, then that's great. Ignorance is bliss. Maybe you just really love McDonalds hamburgers. Maybe that's all you know. But don't tell me that the hamburger is made of the same quality as the filet mignon.
In my opinion, The Dark Knight Rises is not a quality film. Do people love it? Sure. But what's their point of reference? What are their qualifications? Do they have the background or the expertize in film to even know quality when they see it? If 3 or 4 of your 10 favorite movies of all time are Batman movies, or superhero movies in general... isn't it safe to assume that maybe you're a bit bias? Or that perhaps you view cinema with a bit of a limited scope? If we're comparing Nolan's Batman movies to Green Lantern, then sure... they're a masterpiece.
Film is both an art and a science. Believe it or not, there is a method to making an enjoyable film. And when a movie falls flat on it's face, there are reasons for that too. But we all have different standards. To me, when it comes to The Dark Knight Rises... I recognized gargantuan flaws in it's writing, it's direction, it's structure, it's characters, and it's story. Now if you choose to ignore those same flaws, or maybe you don't see those flaws... then all power to you. It's not worth me pointing them all out because you'll just throw them back in my face anyways. If you love the movie, then nothing I say is going to make any sense to you anyways.
Notice i didnt said you were wrong (although you are

t: just because you are making an immense generalization where so much fits that nothing is really consistent).
You make valid points , but you're being a tad too extreme with the objectivity. Off course the opinion of two people dont hold the same value. Off course their knowledge and experience make huge difference. That's why everyone takes under different consideration the opinions of other people. Some hold great value , some....who cares.
But you didn't write this. Well you did some times , other times you are expressing something entirely different.
I think like this. If you don't think like i do...then you are objectively wrong . That's your error. Because i can give you 2 different guys , people with an enormous experience in the medium , with vast experience , submit them to this movie (because it's the one we are talking about) , and they will give you two completely different opinions...yet they are both valid. None of the are ignorant as you implied , just because it's different than yours.
And you made some separation regarding who is able or not to give a bias opinion (off course if someone holds in great affection superhero movies as the cream of the crop of cinema , is extremely bias and probably very limited , but that is an extremely small sample , and again someone who i dont hold their opinion in great value)...what is the line ? You didn't detailed it. Which eras do you have to experience ? Which countries ? Which styles ? Film is such a vast medium , that i have no idea how you will be able to create that line.
As for evaluating objectively a film....well the technical part to an extent sure . Wally's work in 65mm is some of the best in the business. But i know a bunch of photography aficionados who don't like his style , his framing , his blocking , his exposures , etc. Then we have sound , structure , direction , etc. All different areas , probably evaluated with great detail by very specialized people. As an whole ? I'm sorry but the amount of detail that goes to a project like this holds no comparison to a burger. As cool as the analogy is.
All that matters is what you think.
You wrote this , which contradicts some of the stuff you wrote. Now we are leaving completely the objective nature of film , to all that matters is what you think.