And you automatically grant Craigslist your first born child and all future earnings and your left index finger. Laywers love to fill these things with unenforceable outlandish crap. The courts are more discerning.
It says that you own everything you post, but you are granting them the rights to use it. The only unusual bit is that you are additionally granting them the right to go after people who scrape your content on your behalf.