The key words there is intervene.
From my understanding, isn't it that the West (USA and others such as us and the UK, etc) usually intervene to try and put a stop to widespread genocidal, world endangerment (nuclear threat, world/religious domination wars, etc) activities?
In hindsight, many of the interventions by the USA should not have been undertaken, because many of the scuffles they have become involved in are between crowds who have been carrying on and fighting amongst themselves since god was a kid, and these folks will still be carrying on until all our collective backsides don't point towards the ground any longer.
If all these clowns around the world learned to get along and be accepting of others, stop the endless violence and so forth, I'd wager the USA would stay home.
The USA has one of - if not the most - diverse representation of religions, cultures, races and colours in the world.
Western democracies have made mistakes before, but to stand away from all global strives is not a viable option. Australia had participated in two world wars, not of its choice. But, participation in wars of the kind fought in Islamic countries is questionable as advancing Australian Constitutional values.