There is a place for those who think that the equipment is secondary to the photographer and his technique. But there is also a place for people who want to discuss equipment. One should not try to say that others' discussions are worthless.
Contrary to most beliefs, a camera is not just a light tight box, its design and functionality directly affects ease of use, reliability, performance, compatibility, etc. which affects how you use your equipment, what it is great at and what it is not good at.
Ditto, a lens is not just something to focus light with, its very design depends on the optical approach chosen by its designer, what choices have been made wrt the optical aberrations, and thus determines what it is good at and what it is weak at. Thus you can match a lens to a shot if you know what you want to shoot and what you value in a picture.
There's obviously strengths and weaknesses in every lens. It's easy to get religious about C vs N or (in this case) L vs rest of the world. This is unfortunate. But when the price of Leica lenses is so high compared to other lenses, is it not legitimate to ask whether you're getting more for it compared to other lenses?
However, I do think performance should be looked as a whole, and just in terms of optical performance, but also physical performance-- construction, quality of materials, reliability, weather resistance, weight, ruggedness, etc.
