jkjkjk pointed out several points quite well.
I just think it should be added that the Rambam is not just a “mainstay” of Slifkin’s he is in fact the foundational pillar of Slifkin’s logic.
Yet the Rambam himself explictly condemned the approach taken by Slifkin! And it’s not some obscure text, I provided the link, it’s pretty hard to misunderstand the Rambam’s point.
He states expliclty that someone who thinks they know more then Chazal knew, is “cursed” and is a “fool”.
And Rabbi Meisallman does a tremendous job of not just putting forth the Rambam’s shitta, rather he provides the actual text of every source that he qoutes.
He himself writes that he put every effort in providing all primary sources and never relying on secondary or tertiary sources and he demonstrates as such in his book.
I fyou wish to see the relevent discussions and sources of the Rambam you can view go through it in detail in his work, Torah,Chazal, and Science,
Chapters 5,6,7,29,30,33,37,and 42.