If someone makes a statement, and I not only disagree with that statement, but criticize or condemn her for having made it, do I infringe on her freedom of speech?

I don't see how. I think you have exercised your own freedom of speech. Speech acts can conflict with people's freedoms, including freedom of speech--for instance, if I threaten that I will harm you if you express certain opinions. But the beauty of freedom of speech is the idea that it will expose ideas to opposition with the hope that well-informed people will support the better ideas and reject, or if need be, condemn the others.

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