We didn't want Israel to have nukes either, we tried to stop them and failed. We wouldn't bomb Israel's nukes because they -already- have them, and they have grown in a semi-reliable regional ally since then. We are trying to stop Iran from having them at all to prevent them from being essentially off-limits to retaliation (note Iran is the #1 state sponsor of terrorism / people's fears of supporting Ukraine given Russia keeps threatening nuclear action) and kicking off a regional nuclear arms race.