You make a very reasonable point: We all have our preferences, and we should go with the equipment we prefer, regardless of the measurements.
But that's also exactly what
@PyramidElectric said above, in response to your initial comment about this.
So I don't think anyone is disagreeing with you about this fact that individual listening preference is important. Where the disagreement comes in, is when it comes to what individual preference means
for other people, and
for the validity or utility of measurements.
The problem with individual listening preferences is precisely what you say: we don't all hear exactly the same way; we don't all have the same exact preferences; we don't all weight the various trade-off factors the same; and we don't all listen in the same space. (Although it must be noted that extensive research has been done on subjective listening impressions, and some strong human preferences, internationally, have emerged about some aspects of speaker sound reproduction.)
What the existence of differing preferences
means, though, is that your experience is valid for you, but literally meaningless for anyone else.
So if we believe in the value of basic human communication, and of information, then we need to ask if there is any objective information we can get about speakers (and other audio equipment) - and by "objective" is meant "something that can be communicated between us despite the fact that we're different people with different rooms and ears/brains."
The answer is Yes: measurements. And when we talk about measurements in audio, the obvious standard is
fidelity: Low distortion, flat frequency response, and so on.
Now, you don't have to take such measurements as a simple guide to purchases, especially with speakers. But, for example, if Amir measures two different speakers and one has a lot more bass, you can be confident that the one that measures bassier is likely to sound more bassy. Regardless of which speaker measures flatter/more accurate, we can all come to a comparative conclusion that one has more bass. If one speaker has wider dispersion, that tells us that speaker will sound more consistent at different listening locations. Now, if you generally listen by yourself in a dedicated listening room, and you don't tend to get up and wander around much during your listening sessions, then the dispersion issue might not matter as much to you. So you don't have to get the wider-dispersion speaker just because of that measurement. But it gives you information that you - and, crucially, everyone else - can make some rational use of.
Finally, measurements can actually be even
more useful when you combine them with your subjective listening experience. Back to those two hypothetical speakers: If you've actually heard one of them yourself, then Amir's measurements of the other speaker can give you a good idea about whether or not to include it on your audition list. If you heard Speaker A and found it lacking in bass, and Amir measures Speaker B to have more bass than Speaker A, then you might want to check out Speaker B - even if Speaker A measured flatter/better from a fidelity point of view.
As for Amir not having an anechoic chamber, and as for amplification, on those issues you are simply mistaken, as the Klippel measurement system takes room effects and amplification differences out of the equation. That's not an insult towards you - it's just a piece of information about how Amir's measurement system works.