Do you think someone should be arrested for encouraging the burning down of a hotel full of people in real life? If so, why should it be different online? If not, well then you have more serious problems.
I do, but a lot of people don't think it should be possible for the government to track down the person who tweeted let's burn down the migrants hotel.
Does not having government-controlled cameras in our apartments make it impossible for police to prosecute wife-beaters? Can police do some actual work to catch "bad people" as opposed to making internet a panopticon?