Sure, just like you could convince McDonald's to go vegan with a few carefully worded arguments... ISIS doesn't use twitter to debate you. They use it strictly

Sure, just like you could convince McDonald's to go vegan with a few carefully worded arguments... ISIS doesn't use twitter to debate you. They use it strictly for outbound propaganda. Even if you could somehow convince those running ISIS accounts of the folly of their endeavours, these are likely to be a tiny fraction of ISIS' people. There are a few dozen social media people in their ranks, but the idea that the bulk of them even have access to Twitter is somewhat laughable. Denying ISIS such propaganda outlets is useful in fighting them. Proof by the free market theorem: they wouldn't use Twitter if they did not consider it better than the alternatives. They are also better informed about their situation, so they're more likely to be right than anyone else. Denying them this possibility must therefore be damaging to their cause. This idea that extreme ideologies are somehow damaged by access to mass media is among the most ridiculous infatuations HN has embarked on, informed almost exclusively by wishful thinking. An ideology that is pushed underground is, and this is almost a truism, strictly worse off than one that has access to these tools. See the recent reddit paper for some numbers, or consider something like r/the_donald: does anybody really believe that community would have been more powerful if it had been relegated to their own platform early on?