Anyone whose writing and theories are unintelligible, incoherent, divorced from reality, openly mystical or semi mystical, collectivist, anti reason and anti human nature.
Small wonder Ayn Rand is not regarded by today's intellectuals as a philosopher. She is dismissed as simplistic but what her academic enemies hate and fear her for is that she challenges the whole philosophical field since and including Kant and exposes their racket. She points out with ample illustrations how their irrationalist creeds are mere secular versions of the mystic creed and a naked attempt to replace the old feudal kings with their secular variant of the philosopher kings.
Seeing how the renaissance had robbed the Church and mysticism of its powers the new philosophers identified reason as a threat not just to the mystics but to themselves and they knew mysticism had to be saved and set out to destroy reason in order to do it.
Now the philosophers are the masters and they use the same techniques as the mystics of old -unintelligibility, incoherence, irrationalism and their nonsensical nostrums now rule as the mystical ramblings and utterances of the ancient high priests did before them.