Iran have been involved in the war in Ukraine for years. Ukraine has better reasons to fight it than USA or Israel.
Ukraine’s involvement is on the defence, they don’t bomb Iranian cities. And the drones they shoot are not only targeting USA and Israel directly.
Ukraine is still fighting for survival and they have to make some tough choices to fund that fight. Unlike West Europe they can’t just say ‘fuck off, we won’t help you’ to their important or potential arms suppliers.
Yes, it is not a great place for them to be in, but in their current situation I find this is quite justified.