Not true, right-handed neutrinos are a dark matter candidate. They don't experience the weak force, so would only interact through gravity. See recent work by

Not true, right-handed neutrinos are a dark matter candidate. They don't experience the weak force, so would only interact through gravity. See recent work by Neil Turok. This podcast is one of the best popular accounts of his work: The (Simple) Theory That Explains Everything https://www.youtube.com/watch?v=ZUp9x44N3uE https://www.youtube.com/watch?v=ZUp9x44N3uE