A more neutral warning is that Tegmark has moved from conventional science towards untestable speculation. That and the fact that he has cultivated funding sources more aligned with the occult than with science has left many of his peers seemingly resentful.

Unless it can be proven (and he doesn't, at all, prove his case) then there is no reason to not describe it as such.

(Grandiose is the exception - that's a stylistic judgement and quite apt here, irrespective of its truth value)