Can any Idealists explain how Realism is not simply objective reality?

Since the evolution of great world superpowers, (British Empire, Russian Empire) , there has been a more bipolar power dynamic in geopolitics. The Great Game of the 1800s which was the superpowers fighting over hegemony in the Middle East/asia.. is very much the same dynamic as we see today. With the US role supplanting Britain. Clearly, the conflicts in Syria, Iran etc are reminiscent of that. Iran has taken on a role as a Russian proxy , with Russian scientists building up irans nuclear abilities ostensibly as an act of defensive realism, to counter The US proxy Israel’s nuclear ability. This is why regime change in Iran has been discussed since 1980 and we have the shahs son here in US ready to move in (much like Russia has Yanukovych waiting to return to Ukraine). Arguably, the afghan and Iraq wars were fought with an ulterior goal of creating an Iran sandwich that would eventually be used to convert Iran to an American proxy. my question is, how can they idealists observe these things and still believe in idealism? What is the moral case for US not voting against Israel in the UN? It is simply because Israel is our strategic partner in the region who helps advance our realist objectives. There is no moral quandary about it. This stuff trumps any moral question.