No, the home advantage is lost, also Britain has a different climate to that of China. The time the Olympics where on in China the weather was hot and humid not many people stand that, especially if there from cold countries. I don't think Chinese athletes will be at their best. Russia at hand should do better as I think their climate is more suited to UKs.
In fact your wrong, China sent more number of competitors per delegation than the USA. 639 vs 536. Also USA tends to enter more team events than China (plus more athletes used). Russia only sent 467 to the 2008 games
But if we going to use the per number entered sent argument we can argue that Panama is much better it fielded only 4 people and won one gold, if they had sent 639 people like China's team then they would had won 160 gold medals plus beating China on gold medals won per people sent. When there other countries that would be better than China if we did it this way, Mongolia, Kenya, Georgia are just a few that are better this way.
If we really want to get funny about it, we could go the points scoring way ie. gold = 3, Silver 2 Bronze =1 we find.
China = (3 x 51) + (21 x 2) + 28 = 223 pts
USA = (36 x 3) + (38 x 2) + 36 = 220 pts
But then again China did yield a bigger team by about 20 %
Maybe instead of being a Western (USA) hater you should be a little less ignorant about mathematics and statistics.