The community here is heavily centered around Eliezer. I guess if someone started promoting some kind of fake rationality here, sooner or later they would get into conflict with Eliezer, and then most likely lose the support of the community.

For another wannabe rationalist guru it would be better to start their own website, not interact with people on LW, but start recruiting somewhere else, until they have greater user base than LW. At the moment their users notice LW, all they have to do is: 1) publish a few articles about cults and mindkilling, to prime their readers, and 2) publish a critique of LW with hyperlinks to all currently existing critical sources. The proper framing would be that LW is a fringe group which uses "rationality" as applause lights, but fails horribly (insert a lot of quotations and hyperlinks here), and discussing them is really low-status.

It would help if the new rationalist website had a more professional design, and emphasised its compatibility with mainstream science, e.g. by linking to high-status scientific institutions, and sometimes writing completely uncontroversial articles about what those institutions do. In other words, the new website should be optimized to get 100% approval of the RationalWiki community. (For someone trying to do this, becoming a trusted member of RationalWiki community could be a good starting point.)