Since much of their government agrees with their president, who considers Jews to be subhuman trash who pollute the earth with their presence, it isn't over-the-top at all.
Who in the Iranian government thinks this outside of the president of Iran? Secondly, it doesn't matter even what the Iranian president thinks or says since he is nothing more than an impotent figurehead. He has no power at all. He only has the power the religious order that Ali Khamenei heads gives him, and tells him to do.
Additionally, as Rareboy pointed out, Israel is armed to the teeth with both nukes and conventional weapons. If Iran ever struck Israel with a nuke (which will never happen) the retaliation of Israel and the USA would make Iran nothing but a sheet of glass.

