If the Chinese were to behave as you say, it would mean a complete change in nearly 50 years of its foreign policy, from one of passive bystander to active participant. It is difficult for Communist nations to turn 180 degrees because they have large bureaucratic mechanisms that are resistant to change (in many respects like our State Department). These current trips to S America, Africa etc are no different from the Mao era when China sent delegations to 3rd World nations. They really mean nothing as China is incapable of backing it up with military presence.
As to the fifty year thing...50 years ago, would put us in the 1950s. Right after Korea and right after Tibet. They were still consolidating their activites of those invasions/wars. So, please do not so cavalierly cast those aside. In addition, their involvement in Vietnam and with India post date the fifty year mark.
As I said earlier, clearly we disagree on this. I view Red China as the greatest long term military threat we face,particularly as they alingn with Russia, Iran, N. Korea and others, with the potential of a much more active and harmful "cold war" that is much more likely to develop into a hot war.