First, early advocates of cryonics and MNT focused on writings and media aimed at a broad popular audience, before they did much technical, scientific work. These advocates successfully garnered substantial media attention, and this seems to have irritated the most relevant established scientific communities (cryobiology and chemistry, respectively), both because many of the established scientists felt that something with no compelling scientific backing was getting more attention than their own “real” work, and because some of them (inaccurately) suspected that media attention for cryonics and MNT had translated into substantial (but unwarranted) funding for both fields.
Second, early advocates of cryonics and MNT spoke and wrote in a way that was critical and dismissive toward the most relevant mainstream scientific fields, and this contributed further to tensions between advocates of cryonics and MNT and the established scientific communities from which they could have most naturally recruited scientific talent and research funding.
Third, and perhaps largely as a result of these first two issues, these “neighboring” established scientific communities (of cryobiologists and chemists) engaged in substantial “boundary work” to keep advocates of cryonics and MNT excluded. For example, in the case of cryonics: according to an historical account by a cryonicist26 (who may of course be biased), established cryobiologists organized to repeatedly label cryonicists as frauds until cryonicists threatened a lawsuit; they passed over cryonics-associated cryobiologists for promotions within the professional societies, or asked them to resign from those societies, and they also blocked cryonicists from obtaining new society memberships via amendments to the bylaws; they threatened to boycott the only supplier of storage vessels suitable for cryonics, forcing cryonicists to build their own storage vessels; they wrote a letter to the California Board of Funeral Directors and Embalmers urging them to investigate cryonicists and shut them down; and so on.
@lukeprog’s investigation into Cryonics and Molecular nanotechnology seems like it may have relevant lessons for the nascent attempts to build a mass movement around AI safety: