We have no obligation to wait for an aggressive person to strike us first because, in case you all haven't realised it, the first strike an aggressor makes can be the last. Comes down to the likelihood of the use of weapons these days.
If you think that pre-emptive strikes are beneath contempt against an aggressor who (these days) likely is carrying a weapon of some sort, you're putting yourself in a position to be gutted. I know many people (a few of them who are friends) who carry illegal weapons, such as concealed knives.
Remember, the law exists to protect the innocent. I honestly think your sweeping generalisations about pre-emptive strikes makes you a very biased juror and a poor representative of the martial arts. If you don't have the objectivity to distance yourself from your personal feelings regarding the issue and look at the facts surrounding the incidents on a case-by-case basis, you may charge an innocent man/woman guilty and leave a hooligan on the streets to attack someone again, maybe resulting in a murder which could have been easily avoided by good, objective judgement.
Pre-emptive strikes can be justifiable and honourable and can prevent the death of innocents. In these days of regular terrorism, a person who throws a pre-emptive strike could save many lives. Surely this would be an honourable thing? Sweeping generalisations help nothing.
Perhaps you are such an exemplary martial artist that you don't have to worry about being stuck with a shiv/pocket knife by surprise but I sure as heck know that many people are not (including myself). Times have changed in most of the world and it's not as safe a place as it used to be.
_________________________ Self Defense (Website by Marc MacYoung, not me)