I think that it's both a rewriting of history and a rationalization of the investment on some people's parts.

Nixon's opening of relations with China was definitely a move against the USSR, but that was nothing compared to the extent of investment that was seen after the fall of Communism in Europe. The fact that the CPC was still very much in charge while all of this investing was occurring had to be rationalized somehow in the minds of people who were less cynical, and "it'll help liberalization" was probably one of the rationalizations used. And in some ways, you can use investment as a way to leverage social changes within countries, and some people (though apparently not enough) thought that was the intention with China, but there was only a carrot, not a stick, and by the time there was a desire to use a stick, there was too much dependency on China as a market and producer for the West. That's where we're at now.