Considering the article, 50 planned attacks would not result in thousands of convictions, and it isn't known how many of them were in the US (Other countries could have different standards for evidence or may have, in good faith, believed that it was all acquired legally.) Even so, the point was not that some people were convicted of planning attacks but that the attacks were prevented.

Meanwhile, it's the method of prevention that should be disputed, not the fact of it.