That's the essence of political liberalism in the first world countries when it comes to Imperialism. As long as it's conducted effectively, by a mildly charismatic or likeable leader, and the domestic population doesn't suffer any consequences, most people are all for it. The invasion of Iraq was very well publically supported in the early years, and so was the Vietnam War. Obliterating Iraq's extremely incompetent military in the Gulf War and then using Shock and Awe back in 2003, plastering it on TV was easy and popular.

After twenty years of US military capabilities being hollowed out by greed and a severe recruitment crisis, they finally started something with a country that could hit back, and hard. The European "powers" can't do anything either, or they'd be there to help deal with Iran. It's good, but it is also dangerous as you say. Because exposing the weakness of Western imperialism like this will invite more challengers.