Sigh... Let's try again... You say that the ESRB is tantamount to censorship. Censorship implies that the "artists" (in this case game designers) are being stifled because they have to meet certain guidelines set by the ESRB to reach certain ratings correct?
An AO rating doesn't stop a game from being made, it stops it from being sold at many retailers. True artists wouldn't care about whether a game is selling or not, merely that there art and message is getting out there. If you only do art for money, then yes you'll "drop your standards" to match, but that's still not censorship. That's folding on your personal standards to make money.
But it's not the ESRB that is the biggest cause of this, it's the PUBLISHERS that are the biggest cause of artistic and creativity being squashed. They demand that developers make their games certain ways so they are more marketable and that they can make more money from them. We know of MANY instances where big developers have changed (or tried to change) characters/plots/etc to sell more.
Either way, ESRB isn't causing censorship... it would be the retailers for not wanting to carry games with AO ratings, and publishers who are willing to ruin artistic vision for money. Both of those have a far greater influence than the ESRB on content. You could also blame Metacritic too while you're at it.