US cloud companies can be forced by the US government to spy on European citizens. That's the reasoning behind this ruling. Are you not aware of the NSA spying programs?
America engages at global level surveillance. American corporations can be coerced with a single national security level to spy on their customers. Ergo they are untrustworthy and should not be used.
Not a single rule was violated in the post above. Looks like hackernews needs more responsible moderators.