Using that logic, Chinese should cite national security concerns and ban Intel processor, Apple devices or simply anything comes with a US made/designed chip from all those so called "sensitive" government departments. Oh, let's don't forget US made airplanes, still remember the spy bugs placed on the airplane suppose to be used by the former Chinese president? Sounds like a national security threat to me.
http://www.telegraph.co.uk/news/worldnews/northamerica/usa/1...
(It is worth noting that these remarks came in the middle of a bidding war between Ant and Euronet (https://techcrunch.com/2017/03/14/euronet-alibaba-ant-financ...). Take the situation however you want...)
Either way, other articles (https://www.theverge.com/2017/5/9/15595338/alipay-us-expansi...) point out that Alipay has a presence in the United States... the concern seemed pretty specific, and not really like the wholesale blocking of major American (and other) sites that China engages in.