The real danger is that they would still think it, even if they did not have an online venue, and when they feel safe they offer sympathetic support to those that will act on their hatred. The more echo's heard in the echo chamber the more empowered those that will act feel, at some point they will feel that their actions will be accepted or at least not countered, and at some point they will be right. I am not arguing against free speech by any means. The hate is still there even if they cant say it, so limiting speech only serves to treat the symptoms and not the infection. As well limiting speech also has the nasty side affect of limiting the ideas of those that are not in power, even if they have the moral high-ground. Unfortunately the only solution to fixing this infectious thinking is good old fashion education which seems to be a harder and harder thing to do. Willful ignorance is a merit badge now days and we celebrate it as being the epicenter of our culture by idolizing individuals that so predominately display the characteristic.