If you're going to say "why only now..." and say you don't understand the author's mindset for conditioning his concerns on who is in power, then yes, you do have an obilgation to back that up.
Trump's election just means the threats will be much greater, and the battles a lot harder to win.
It's true that some of Trump's institutional changes might take decades to undo.
It's his job to justify sentiments like that. Without it, it's an out of context blog post. If you expect the reader to go back and read an author's past history to understand those assumptions in the text, then you are expecting a lot of the reader and not much of the writer.
But again, my question is: what practically signals that Internet freedoms under Trump will be worse than they would be under Clinton? I see nothing to suggest that Clinton wouldn't be similar to Obama. Why is Trump worse?