We are here to discuss what is more important and why, not discussing my way of building
I think the issue here Zektor, is that most of us do not believe that one is more important then the other. And as noted, many ships that are "Pretty" are very capable of holding their own vs an optimized doom cube. AND the small % difference in systems (We are likely not talking more then 10-15 percent IMO) is not enough to sway most battles. This means, that most people are willing to look bad-ass and feed their own ego for that small loss in effectiveness.
I think your question is based on flawed logic. You claim you can't be functional AND effective, when you can. IF you assume you CAN have both, like some people have argued, then the question would be more aptly worded as follows:
Why do we not worry about the small percent loss in effectiveness, in order to make our ships look good?
The answer to that could be many things. It could be "Because I don't want to look like a noob" or "Because I want my ship to look as destructive as it actualy is" or any combination of arguments as it is totally subjective at that point. And that is where the "Philosophy" can come into play.
However due to your assumption that effective and pretty cannot exist at the same time, you have in effect changed the topic yourself from "why build pretty things" to "I think you can't have both, why do you guys bother". SO the answers you got were "you CAN have both, and this is why we bother".
Instead of "I build good looking things because X".
If you went into this discussion without some preconception that you cant have a ship that can survive PvP AND have it look good I think you may have gotten the responses and type of discussion you were interested in rather then the argument you currently are trying desperately to put out.
But that's just my subjective 2 cents, take it how you will.