This title is a ridiculous clickbait. Read the original article from La Quadrature du net for actual context.
I do agree that this case takes way too many shortcuts about privacy/encryption to flag these people as terrorists. However, the people depicted in this case are not just using an adblocker. They run Tails, Tor and signal "by default" and at all times, which I doubt is the case of anyone calling themselves a "terrorist" in this thread. Doing so require a huge commitment in one's life, and that's what the police is using as "proofs" for their suspicions. And that's the part that is fucked up, because it's basically duck typing applied in a court. They have no proof of anything, and just suspect these people because they take a lot of extra steps to protect their privacy and anonymity.
As a French people myself, I'm glad that La Quadrature is stepping in to prevent the judge to take this ridiculous shortcuts as proofs. However, as someone using Signal, Tor and adblockers daily, I don't feel like I have anything to fear. Yet.