Two key differences explain why one nation’s plight receives more sympathy than the other’s.
On April 13, the Islamic Republic of Iran launched missiles and drones at Israel. Also on April 13, as well as on April 12, 14, and 15, the Russian Federation launched missiles and drones at Ukraine—including some designed in Iran.
Few of the weapons launched by Iran hit their mark. Instead, American and European airplanes, alongside Israeli and even Jordanian airplanes, knocked the drones and missiles out of the sky.
By contrast, some of the attacks launched by Russia did destroy their targets. Ukraine, acting alone, and—thanks to the Republican leadership in the U.S. House of Representatives—running short on defensive ammunition, was unable to knock all of the drones and missiles out of the sky. On April 12 Russian strikes badly damaged an energy facility in Dnipropetrovsk. On April 13, a 61-year-old woman and 68-year-old man were killed by a Russian strike in Kharkiv. On April 14, an aerial bomb hit an apartment building in Ocheretyne, killing one and injuring two. On April 15, a Russian guided missile hit a school and killed at least two more people in the Kharkiv region.
Why the difference in reaction? Why did American and European jets scramble to help Israel, but not Ukraine?
tl;dr: no one wants an upset nuclear state (Israel), and the Republicans are thoroughly subject to Russian propaganda, influence and bribes.