WeChat is not blocked, just like a long list of US internet services not blocked in China - Amazon, NH, booking.com, ebay, uber, airbnb, expedia and many more.

That being said, Huawei and Alipay's expansion into the US has been repeatedly blocked by the US federal government [1]. By citing the same national security concerns, using such logic, Cisco and Microsoft should have long been banned in China - but they are not, both are making good $ in China.

[1] https://www.reuters.com/article/us-moneygram-intl-m-a-ant-fi...

Those companies had to obtain ICP licenses and participate in forced partnerships and open up their servers to the government.

Your claim of fairness here is simply quite laughable

Huawei would like to participate in "forced" partnership and open their servers to the US government in exchange US market access. But still, it's banned by national security. laughable?

>Well I guess they shouldn't have put a backdoor in their products then.

Citation needed. I've yet to see any evidence against Huawei and ZTE. Just FUD from the USG.

Cisco is full of backdoors either.

It seems like you undermined your own point here.