"nine out of ten 'ethical' hackers are being a bit naughty..."
There's no need for the quotes around the word ethical. if your community ethics include being naughty, then it's OK within your community. The problem arises only when the ethical systems of different communities are in conflict.
However at least in the UK, such activities are potentially unlawful. They could therefore backfire badly supposing service providers and law enforcement really gave a hoot, but they don't really seem to so the habit gets reinforced until it becomes a norm.