I am assuming that by "Vietnam support" you mean the support of American proponents for US troops taking active part in the war between North and South Vietnam.
Your baseless analogy that suggests I support foreign troops actively participating in the military actions against Russian aggression in Ukraine is in no way reflected in my post and is absolutely false. Likewise, nowhere in my post did I voice support for the war in general. Nor am I concerned with stopping the spread of Russia's delusional ambitions of imperial grandeur: a child can see that Russia is incapable of sustaining it under any circumstances.
Your parallel may have been more plausible I were defending Russia's aggression against Ukraine, but even then it would be stretching it too far.
What I am supporting is the right of an independent sovereign internationally recognized state to defend its borders and its right to exist in the face of open military aggression. Hence my demand for respecting Ukraine's flag.
So are you against a country's right to self-defense? Are you in favor of one country annexing another country's territory through waging war? If so, your pacifism is very peculiar. And if not, how do you think you can stop the war by negotiating an agreement with a habitual aggressor (Russia) who repeatedly invades a sovereign state (Ukraine) in violation of every single previously negotiated agreement?