James Rolfe, a YouTube celebrity with 2.1 million subscribers for his Cinemassacre channel, blasted the forthcoming remake of Ghostbusters. In a six-minute comment, Mr. Rolfe went on to shatter the release, most unusually saying that he was not going to watch it, on principle: why put your money on something you dislike? It makes sense, in a way. He is an adoring fan of the original Ghostbusters, the 1984 classic. So far, so good, or perhaps not so good for Mr. Rolfe. His audience soon split between supporters and sworn enemies. Among the latter, some went even as far as to make death threats against him. Yes, you read right, death threats over a comedy, or rather, an unfavorable comment over a comedy not seen by the reviewer. Other than a number of profanities he could have done without, Mr. Rolfe’s comment is even-headed. He’s just explaining his decision not to review a movie he will not watch. We did not perceive any sexist whiff, as some of his critics said, as the new Ghostbusters are women. Yet the Mr. Rolfe case is remarkable for two things: how online communities (if we can call them that) from YouTube audiences to social networks, have a propensity for polarization; and the fact that neither Mr. Rolfe nor any of his supporters and critics saw the movie. Some, as Mr. Rolfe himself pointed out, did not even see his online comment, or not in its entirety: hearsay was enough to launch on their tirades. These are fast times indeed. But take a moment, or two, to see what you are declaring your support for, or opposition against.