Because they know, like everyone else, that opt-out results in more people not opting out. Again, this is for the people using JetBrains IDEs for _free_. You c

Because they know, like everyone else, that opt-out results in more people not opting out. Again, this is for the people using JetBrains IDEs for _free_. You can pay for a subscription and it becomes opt-in. I think it's completely reasonable for it to be opt-out or even required for the free product. Giving non-paying people a choice is a step above what I feel they are required to do (morally, ethically, etc).