[swingdjted]

It may not in theory, but in practice, the powers that be have discovered that this works better than any alternative attempted in the past.

I'm being pretty vague here, but really, it's a matter of who does what, through which means, and from where. Equal isn't always fair and fair is not always equal, etc. It's mostly just a balancing issue - answering the question of what prevents problems the most while inconveniencing as few well-meaning potential members as possible.