Is "AI" truly intelligent, or is it more "self trainable"?

Out of curiosity, I’ve recently been exploring some AI sites. I’ve noticed, at least on some text-to-image sites, the AI’s interpretation seems to lean towards NSFW material (or outright porn). Is this because a particular AI is learning from user input, or is it because there’s so much NSFW material (including pornography) on the interwebs that the AI “learns” as if porn and NSFW content are the norm?