It has been long identified that these extremist groups can be best curbed by not letting them have access to audiences. Unfortunately now that they do it is likely that our countries are facing a new wave of violent extremism and terrorism. Free speech sounds wonderful, until you give an extremist group the power it needs to put knives, guns and bombs into the hands of isolated or disenfranchised people.
Obviously the other solution is to not leave people behind, to not let them be isolated and disenfranchised in the first place. The problem is that in some countries like the United States many politicians are working on the opposite, because that's how they themselves get elected.
They definitely use phones too, so does that mean the Patriot Act is justified, and governments should tap into everyone's personal life? These are extremists, so they shouldn't be given a platform to communicate, and to achieve that, it has to be a solution that encompasses all users. This not only leads to false negatives, but abuse of power. At best this is lazy governing, solving a problem with a lot of collateral damage, at worse this is done purposefully to control the citizenry.
The key to a healthy society is a big fat cushion at the bottom people can land on if they need be. Unlike what conservatives and libertarians say most people will want to do more with their lives than just to sit on the cushion, but even them sitting on it is cheaper than leaving people behind, because people get damaged, turn around and spread that damage like a disease, and from then on you are fighting a cumulative network effect.
It should not be a secret that if you suspect people of being potential terrorists, that they might not like you or anyone you are associated with. And maybe they will then just support those you dislike.
I think you are a victim of war propaganda that you perceive this as a significant threat. You are the extremist you try to call out. Without any evidence aside from maybe some rude internet chat from computer gamers. This is a complete insane assessment.
Ah yes, the ol’ free speech to terrorism pipeline.
Not everyone deserves a voice, but even if you do we don't have to listen. We don't have to tolerate intolerance either, we are perfectly free to not tolerate it, in fact we must.
If you are curious who decides about who deserves a voice and who don't this is something they teach in high school, though not everyone receives civic education unfortunately.