You don't get it, Pakistan was a close ally of USA for many decades but that ended very fast. Many people rejoiced the 9/11 attacks and condemned the killing of OBL in Pakistan. It is logical that at present Pakistan and China are close friends but once the benefit is over then atheist China can never be a friend.
This is the reality for every religion especially monotheistic religions. No monotheistic religion can support any other religion but their own.
At the end of the day we are all selfish and because of our selfishness we are even willing to not accept our own mistakes.
In that case let's just agree to disagree. U r citing the deterioration of US/Pak relations as an example that supports ur view of religious differences. That simply is not the case.
US/Pak became allies bcuz of their interests and moved apart somewhat bcuz of their interests. If a state's religion(or the religion of its majority) determined whether countries become allies or enemies then Pak and Japan would've been enemies. Or how about Vietnam? Or any other non Muslim country for that matter. That is simply not the case. Pak's relations with all other countries are interest based. Sharing the same religion can add to it due to solidarity but if religions are different it doesn't effect those relations adversely.
A lot of Indians, at least on PDF, seem to think that the alliance between China/Pak is momentary due to common enemy(India). I disagree with this assessment.
There was a time when China was in shambles, very poor economically and way behind technologically. During this time Pakistan had nothing to gain from China. It could expect no help financially nor any tech assistance(defence equipment) from China against India. Yet they were still allies and not enemies. Why? Bcuz China didn't pose a threat to Pak and Pak didn't pose a threat to China. They didn't go after each other's territory. Another reason is that no country would want to make an enemy(specially in their own neighborhood) for no apparent reason. Most countries only become enemies when there is conflict of interest. If there isn't a conflict of interest then worst case scenario is that they just don't care about each other...like Luxembourg and Pak for example...not allies per se but not enemies...they just exist.
Even in absence of India being a common enemy, China and Pakistan would still be fine with each other, at worst akin to Iran/Pak relations) and at best like how they already are.
As for 9/11 rejoicing thing...
No sane person(regardless of their religion/nationality/etc.) is going to celebrate brutal/senseless killing of innocent ppl. I'm Pakistani and I didn't. Of all the Pakistanis that I know, none of them rejoiced over it. Though there could be those who did(since I can't speak for all) but again that has more to do with this recent trend of Islam being hijacked by idiots/psychopaths(the likes of ISIS). These ppl have started using it as a tool for their own gains. If any rejoiced 9/11 it must be these a**holes or their followers, hence also a**holes.