Why would Europe sit idly by while the US unilaterally reshapes their energy policies?

And we're talking about 50 meters of a pipeline several hundred KMs long. It's a trivial repair job compared to the effort to build the pipeline and its economic value. It temporarily changes the calculus but doesn't change the long term picture if Germany still wants to buy gas from Russia.

Plus, it seems likely to galvanize Europe into becoming much more of an independent actor. Destroying a major energy source is pretty far over the line of how you'd expect allies to treat each other. It would be a dramatic step and thus far the response has been pretty drama free.