Though alleged nutjob Jack Thompson would have you believe that every other game that comes out these days should have an "M" rating from the ESRB, the opposite is, in fact, true. Statistically speaking, according to the ESRB, the number of M-rated games have been cut in half since 2005, and make up roughly 6% of the gaming market, which is dominated by games that are rated "E" for "Everyone."
Now, why would people want you to believe otherwise? Might have something to do with the fact that it's a political chip in the favor of a lot of elected officials, and the more that they can keep your elders scared about what the young whippersnappers in their lives are up to, and the more they can con them into thinking they're the only solution, the more votes they are likely to attract come election time.
You are now armed with information. Use it at will.