A realist would point our that our allies are also spying on us and the outrage is a facade being leveraged for political ends.

Or not. Merkel doesn't seem to care much anymore. They probably knew this was happening. It was just embarrassing that suddenly the public also knew.

That realist would be a fool who takes the exasperated statements of politicians at face-value. Were any long term trade agreements threatened? Embargoed in a way where they actually did it, not just talked about it? Was military cooperation withdrawn, diplomatic ties severed?

Absolutely none of this happened. A lot of words happened. Mysteriously, for exactly as long as Snowden was in the news right up till Russia invaded the Ukraine.