There is of course a valid answer, which is that the Cold War is over, and we no longer face the prospect, which was extremely grave and serious at the time, of Communism attempting a slow motion world conquest. In that context, for both principled and pragmatic reasons, simply allowing any part of the world to fall to Communism was a dereliction of duty.

But today the Beijing regime is if anything a conventional authoritarian state at this point with only a veneer of Marxism retained for the sake of minimal continuity, and dealings with it can be had on a conventional Great Power to Great Power basis, rather than in the context of a planet-wide struggle between two multi-national and universalist ideologies.