TBH Lewis is probably in a better place fair-use-wise compared to his fellow "reviewers". The fact he is working from a print medium means he must scan and act out parts of the comics he wants to talk about. This means he uses only what's necessary for the review rather than the whole thing, and he is being "transformative" by transferring to an audio-visual medium. Plus, he is so damn whiny that his reviews can't help but contain commentary (read: complaining).
That doesn't mean DC or Marvel couldn't fuck up his day if they wanted... But chances are they either aren't aware, or do not care about the obscure internet guru shitting on 30-year-old comics.