In the context of a lot of Reddit alternatives, the argument of 'not literally illegal' isn't always what is being made. Sometimes it's more along the lines of 'stop interfering with our law breaking' or 'let us openly promote real workd violence'. Sometimes people have migrated to sites where the administration is either legally insulated by strong local laws (ie: Voat in Switzerland), or otherwise ambivalent attitudes towards actually following regulations (Chan sites, self-hosted forms). The incel communities, and many other violent communities come to mind right away.