It's pretty funny - I might have missed some, but the MSM and even the conservative sites are pretty quick to mention any ragging on most everyone else in Trump's cabinet. I have yet to see any of the dems or lib sites attack Mattis in any substantial way. I think they really are afraid of him.
I have to say I'd really like to see an SJW/Mattis encounter in the same way they confronted Betsy DeVos. That would require a whole barrel of popcorn.