Iran is right not to recognize the legitimacy of the Israeli state, because it was recently created via a violent settler-colonial occupation culminating in a genocide. It's not black and white, but it isn't completely fucking gray either, and there are some parts of this that are black and white.

From the American Declaration of Independence:

We hold these Truths to be self-evident, that all Men are created equal, that they are endowed by their Creator with certain unalienable Rights, that among these are Life, Liberty, and the Pursuit of Happiness—-That to secure these Rights, Governments are instituted among Men, deriving their just Powers from the Consent of the Governed, that whenever any Form of Government becomes destructive of these Ends, it is the Right of the People to alter or to abolish it, and to institute new Government, laying its Foundation on such Principles, and organizing its Powers in such Form, as to them shall seem most likely to effect their Safety and Happiness.

Israel de facto governs the Palestinian people without their consent, depriving them of all rights and treating them as disposable. In this case where Israel has refused all attempts of the Palestinians to alter this arrangement the only path that remains to them is to abolish the Israeli state, as is their right. Israel does not have a right to exist and no other state does either. The existence of any state is a privilege derived from the consent of the governed.

Your right, there's tons of historical context here.

You act like this attitude twords the US and its allies are in a vacuum.

You act like Israel doesn't have nukes treating them as well, funding terror in the region themselves. Gaza and Lebanon come to mind.

Why should Iran cozy up to such a hostile nation?

They're not. There rooted in the blood spilled by those same countries.

If the US is hated, it's probably justified.

Israel has a long history of funding terrorism as well. In the 1950s, Zionists secretly performed terrorist attacks on Jewish synagogues and communities around the middle east. This was done in an effort to make them feel unsafe in Arab countries to promote migrations to the newly-formed country of Israel. Before this, Jewish people largely lived at peace alongside Muslims, as they were traditionally considered "People of the Book" due to their shared Abrahamic-religious background.

Furthermore, Netanyahu's government has a history of funding Hamas to prevent the more moderate Palestinian Authority from representing Palestinians. Up until Oct. 7, Netanyahu was funneling 35 million dollars a month to Hamas through Qatar, with over 1 billion dollars transferred in total. He would do anything to prevent a two-state solution, and was also desperate for a distraction from his 10-year long corruption investigation.