I think the assumption behind your claim of false equivalency is exactly what the parent comment wanted to discuss.
You say the security failings of iMessage and WhatsApp pale in comparison to WeChat; I agree with parent comment and ask - in light of PRISM etc. - on what grounds can you say we should not be just as suspicious?
Whether or not compromised, I am sure my messages on iMessage are not used to train censorship applications by the NSA. Messages on WeChat are used for censorship.
I also, separately, think that in aggregate Apple has incentives to make iMessage secure. While Tencent has incentives to share WeChat data with CCP.
These are among many reasons why the comparison was false equivalence. The world is not just black and white “secure vs not secure.”
To your question: Relative transparency and relative accountability of the governments in question.
But your question is by nature setting up a false comparison. There is no observed censorship apparatus in place in the US. You can always pose "what if" scenarios about super classified efforts, but functionally there is no active system in place.
Compare this to the vastly-resourced, all-encompassing one operated openly and enthusiastically by the CCP.
On the basis that there is no automatic censorship of user content shown to me via iMessage. I am highly certain that my friends can send me arbitrary (within technical reason) text and images and not get censored. This is not the case with WeChat in China right now.
Given societal norms I think there is a strong expectation that my iMessages will not be censored in the near future either.
This means there is little incentive for NSA to train and develop an actionable automatic censorship application.
Again, this is true even if they intercept, decode, analyze, commit physical action on the basis of the analysis, and store every one of my messages.
Ah, sorry, I erroneously read "censorship" as "surveillance".
I suppose there is not really the same kind of overt deployed censorship in the US like there is in China. I do personally think that the NSA somehow gets most messages sent in the US, but I have no idea what they would do with it or if that hypothesis is reasonable.
You say the security failings of iMessage and WhatsApp pale in comparison to WeChat; I agree with parent comment and ask - in light of PRISM etc. - on what grounds can you say we should not be just as suspicious?