Yellen cites 'potential dangers' in U.S. stock valuations 11 years ago
We are mixing up a few things here.
1) Has the oil boom benefited anybody? Yes it has.
2) Has the oil boom benefited morally/politically sympathetic groups, such as the American poor? Yes it has.
3) Will the oil boom benefit humanity as a whole, over the medium to long term? The jury is still out on this one, and the answer may in fact be no.
It is perfectly possible to do things that are beneficial in the short run but ruinous in the long run.