You have got a fair point about the over population and other problems tourists may suffer if they visit China in large enough numbers. Also, I don't know whether you are aware of it or not. but there seems to be some health concerns with Chinese street food, about the way they recycle the oil and things similar to that.
You can search "gutter oil" on the internet if you feel like.
Perhaps instead Chine people would prefer Japan, Taiwan or Vietnam?
It would be refreshing to see some World Cup in an oriental setting this decade.
It will be wrong to use one-off incidents to tarnish the entire country. I have seen the video of "gutter oil scandal", but I don't know how authentic it is. Anyway, China is a huge country with a population of 1.4 billion, and isolated incidents can't be used to generalize the nation. Personally I would love to see FIFA world cup being hosted by China. If Japan and South Korea can host the tournament, then why not China? And I don't think that tourists will face any issues related to food, as a lot of US-based fast-food outlets are available at every nook and corner of China.
China is a totalitarian dump, and food has nothing to do with it. Read, for example, the monstrous story about Peng Shuai - this tennis player (moreover, world-famous) simply disappeared when she accused an official of sexual violence. Imagine what happens to ordinary people there. I don't think there should be any international competition in shitty countries like China.
If FIFA agrees that the internal politics of a country immediately disqualify it to be a host, then I can say it is fair to reconsider China. In those cases still I would like to see the World Cup be host in the closest location to the Chinese culture, Taiwan is highly democratic and free but the political tensions between China and Taiwan would also disqualify it, some people would not feel safe being there and I do not know if a country like Vietnam or Mongolia has the economical resources to invest them in hosting an important event like that...
Sometimes because of the better hosting situation of the teams, FIFA let countries host the world cup for example we know China as a communist country, and talking about the politics of that country, that's enough for FIFA to disqualify this country, but China got a strong financial system and they can spend enough money for the world cup which can be a reason for FILFA to let them host the world cup.
Those who spend the most money usually get what they want. We saw this most recently at the World Cup hosted by Qatar. We have never witnessed the world cup in the interim period until now, but Qatar made it accepted because they spent serious money. It also banned the sale of liquor in the stadium, and FIFA couldn't say anything about it. Maybe it will host in China. Everything is possible in the future.
Yes, unfortunately it is true, money rules everything, including football.
FIFA has become famous in recent years due to corruption, the arrest of its presidents and suspicious actions regarding the allocation of the hosts of the world cups.
Football is becoming more and more a business and less and less a game for the masses.
World Cup in China, why not? A new big market for FIFA and a lot of money for FIFA again.

FIFA is ready for anything, even deviating from its fundamental principles and rules for the purpose of making profit.