I do try to push boundaries in my stream. But yeah, my content is consistent with other content I've seen on the sexy streams on ImgFlip.
The MOD didn't say this, but it appears that the pattern based on the images they unfeatured is that they are mostly objecting to cropped depictions of sex between two human beings. I thought cropped porn was okay: it is a whole meme genre unto itself and I believe I've seen it elsewhere on this site. Cropped porn as a meme genre is not truly pornography, in my opinion.
The MOD did also unfeature one gif of female solo sex, while they allowed another gif to remain up on the stream. In the one that was unfeatured, the female was naked (no exposed genitalia), while in the other gif that remained, she was wearing a top. I'm not sure how one is "porn" but the other isn't.
I actually know of another stream on ImgFlip where actual depictions of real sex (including genitalia) have been allowed to stay up for at least several weeks. Probably because that stream just hasn't reached the attention of a mod yet. I'm not going to link it, because I don't want them to get in trouble, but you can find it if you look through my subscribed streams.
Another instance of hypocrisy -- because my stream is getting followers and attention it gets more scrutiny than other streams whose content clearly breaks the rules. Oh well.