Aksai Chin doesn't have much to offer to Indians. I think they were just being greedy. On the other hand China needs Aksai Chin to build a national highway linking to Xinjiang. I think the deal back then Arunachal Pradesh in exchange for Aksai Chin was very gentlemanly to the Indians, I simply don't see why they didn't agree back then. China has settled most of its land borders, but not the ones with India. They're being intransigent.It was the other way around actually. China offered to recognize South Tibet as Arunachal Pradesh in exchange for Indian recognition of Aksai Chin as Chinese territory. Naturally, the Indians rejected, which is responsible for the sorry predicament they are in today.
Err, Russia did take former Chinese lands by force. It then forced Imperial China to agree to that territorial annexation via the aforementioned treaties. China didn't get anything in return from Russia. That's why they're referred to as unequal treaties.
If people want to advance the argument that China will put historic grievances aside and make equitable, win-win agreements with countries today, I'll drink to that. But such a view would be incompatible with an opinion that "China will punish anyone who tries to take her territory" unless we're only talking about territory that China is holding in reality today (as opposed to territory not controlled by the PRC that it says it should control because of historical claims).
Russia is a partner today, India isn't... And that challenge to the Soviets was at a time when China was still the weaker side.
That sounds a lot like saying China can accept unequal treaties so long as it gets on with the other country, which would be contrary to previous Chinese government positions that unresolved unequal treaties would be a barrier to good relations.
Another user said that China would always punish another country that tried to take its territory, but that doesn't make a lot of sense in this context because as far as I'm aware the consensus on this forum is that India has not moved the border in its favour and it's China that has made advances.
So far I've had one helpful response. Maybe other users simply doesn't know the answer (but won't admit it).