If they want to please the government they'd just pay more local tax.
In China there isn't really a private/public divide like the U.S., bribing and knowing people in government is absolutely essential in China. Sure, it helps in the U.S. (and every other country), but it's not essential. China is a different beast. Doing business in mainland China is quite the experience, I know of no one who actually likes doing it. The Chinese are still communists after all, and if you have a supplier there...they are not loyal. They will knock your stuff off in a heart beat as soon as you leave.
There absolutely still is a difference between private and state-owned companies. There are even cases where Huawei loses government contracts to Cisco. Like you said, the water is murky in China, and the favor of Chinese government cannot just be bought by a tiny investment such as this.
There is no guarantee that just because you are a Chinese company, the government will be on your good side. At one point Alipay was almost banned due to some central bank regulation. Didi also has a competitor named Kuaidi, which for all we know can have even deeper connections with the CPC.
To me, this deal is about "You can sell XXX, if you do YYY" YYY may be investment, technology transfer, many things. But a lot of China deals and inward investment in R&D, Operations or Technology are in fact driven by sales. "We need to sell this, and in order to do so, we've been told we also need to YYY."
You need to answer your own question, that is even if Apple's intention is to please government, why would they choose to invest in a ride-sharing company? Why not choose to build a completely isolated iBooks/iTunes store and grant government free access for censorship, that won't cost 1 billion.