This is just indicative of the problem that Tumblr has had for the past couple of years.
They were bought by Verizon from Yahoo last year and so to appeal to the investors, they've launched an NSFW purge with a poorly implemented algorithm. People have done experiments, including one where they've taken a photo of a Japanese water cake, copied and changed the colour in three of them, usually pink, blue and green. Guess which one got flagged? Yep, the pink one. There's been another where they did the same thing with an exposed breast and its only been the pink one that has been tagged. Its literally only looking at the colour.
My guess is, the comics were dropped because of the algorithm picked up the colours from some of the outfits.
But more importantly, its only been artists and content creators that have been hit by this. Right-wing blogs have been untouched, as have white power blogs. Basically, Tumblr has become the shithole it always said it would never be.