There is a difference, basically the entire world hates the Iranian regime and wants them gone, USA bombing the Iranian regime wont get that much pushback from the world even if the war was started in an underhanded way.

It is entirely different if USA starts attacking NATO allies such as Denmark which isn't a threat or problem to anyone, that is not something anybody would expect and it would ruin American diplomacy completely.

Iran has been in a war with the USA since at least 1979. I was about to say "soft war" but that would be ignoring all the deaths.

This is one battle of many and the USA will win it. Whether it is warranted or whether the USA will win 'the war' is another thing.