I think the coverage and response is to do with immediacy and agency.
The murder of 36,00 protesters in Iran is horrendous but is in many ways unconnected to us (beyond our role in overthrowing a semi-democratic government in the 50s to put a puppet monarch on the throne who we supported through repression so we had access to the oil, that led to the current regime overthrowing him in 1978/79). Iran is a pariah mainly due to the leadership but also due to the erroneous sanctions that have made life so much harder for the people of Iran but not the elite it is meant to punish.
America is much more immediate and relevant to the UK as a major ally, a place with massive links to us, and a similar culture that is perhaps a window to the unfortunate direction of travel that this country is taking if Putin's other puppet ever gets elected here.
Similar inconsistency ("hypocrisy") over Gaza and Sudan or any other genocide or ethnic cleansing. We are perhaps more invested in Gaza and Israel as we have direct responsibility for the creation of Israel and we sell weapons to the Israelis so the populace feel more invested in that issue than Sudan or Myanmar or wherever. Israel is also a country on the edges of the European/Western sphere and the Israeli population look quite similar to us (mainly because most of them are actually first or second generation Europeans).
There is some western hypocrisy, and probably conscious and sub-conscious racism, for sure - we are more invested in people and cultures that resemble ours but we are more concerned about situations that may have a direct impact on us economically, culturally, politically - hence USA, Ukraine, Israel take a higher profile and attention than Iran or non-western far away countries.
Don't think it is left/right thing. Must have missed Farage and all the poster boys of the anti-woke, anti-antifa, right of centre brains trust coming out with tweets and posts about Iran in greater numbers than the left. But then Iran has strong links to the Kremlin as well.