It is not defeatist to understand and acknowledge reality.
Why play online games at all? Not sure what that has to do with anything and I don't see where there is a choice in many games. I occasionally play mechwarrior online because there is no other option except online play. I've played countless other online games where there was no other option. I find I generally do not like others intruding upon my relaxation time. I will have an option with Elite and I choose to exercise that option. Why is it important to you to take away that option?
If I may barge in with a poorly constructed analogy, imagine we all got together for a game of soccer and you decided you're going to be playing by yourself, with your own ball, on the same field. You won't touch anyone and no one is allowed to interfere with you, except that you can score goals for whatever team you choose.
That's why.
But as I said, I might be wrong, maybe players will have such negligible impact on the overall simulation I'm fretting about nothing.