Haven't you also seen the exact same arguments from the opposite perspective about why the syllabus shouldn't contain dead white men, regardless of what they wrote? (That is: tradition is oppressive so we must remove it; this author is difficult so we must remove them; we should introduce them but only to criticize them.)

Of course this isn't to say that high-quality discourse shouldn’t be expected of those who argue for keeping much or all of traditional syllabi. Of course it should! The point is just that the people with that view should, once convinced to debate their viewpoints using sound argumentation, also have high-quality discourse available from those with different perspectives.