In my experience, government-issued travel advisories serve two purposes: (a) giving government press officers something to defend themselves with if some visiting tourists do something stupid and get into trouble; (b) providing some extra diplomatic tools for negotiating with foreign states ("if you do/don't that, we'll change our travel advice"). I'd say unless you have some specific connection with the Chinese state or are planning to do something controversial, you'll be totally fine, and can safely ignore this travel advice.

That said, if you think you'll spend your entire holiday worrying about whether or not you'll be allowed to leave the country, I'd choose to go somewhere else and have a relaxing holiday. But I don't think you have anything at all to worry about, based on the facts you've provided above.