Iran has sponsored, built and trained organizations all over the middle east so they could destroy Israel: Hamas, the Houthis in Yemen, Hezbollah in Lebanon and groups in Iraq are all proxies propped up by Iran.
Iran was the first to attack Israel, this happened in 2024 when Israel killed Nasrallah (Hezbollah) and Iran fired hundreds of ballistic missiles directly at Israel.
Iran hates the US way more than Israel, but Israel is closer so obviously they are directing their efforts according to what's plausible. Iran calls the US and Israel "the big satan" and "little satan" in almost all internal communication. Just a couple of weeks ago the entire Iranian parliament chanted "death to America" and "death to Israel" (you can see the videos online). Iran had US flags laid out on the floor of their facilities so that anyone going by will walk over the US flag.
Despite being very uncomfortable, the war is probably necessary because as seen by Iran's attack on Diego Garcia, they have way longer range than previously thought, they have a deposit or military grade uranium enough for 10-12 bombs, they were completely dishonest about their nuclear programs, and waiting until Iran had nukes meant you couldn't ever stop them. You'd have another North Korea but ten times worse, as the Iranian regime is truly a fundamentalist insane leadership. Trump may be unhinged but he's right about Iran using nukes if they had them.