Is there even any evidence that he attended this dinner?
... that and having a taste for pretentious shock-art is not a crime last I checked. I've had a little bit of contact with East Coast elite circles before and that kind of vapid modern "aaaaaht" is par for the course. Never saw anything quite as over the top as Abromovic but I definitely saw things in the same shock-jocking coated with art school babble genre. I always figured it was a stuff people pretended to like for social signaling purposes.
I don't consider all the pizzagate claims impossible. Blackmail has historically been a tool of political manipulation and so a high placed blackmail ring is not unthinkable. I just consider them unlikely, especially in light of the (IMHO rather obvious) existence of an intentional cyber warfare and propaganda campaign against the Clinton presidential campaign.
I've become even more suspicious after listening to one or two interviews about "pizzagate" and hearing the following names and sources mentioned repeatedly: Brietbart news, gab.ai, 4chan, and the Washington Times. The latter is owned by a front for the Unification Church. The first two are pretty well known alt.right outlets, and 4chan is not exactly known for being a forum for unbiased rigorously vetted investigative journalism. (Nor is Reddit.)
https://en.wikipedia.org/wiki/The_Washington_Times
The sources for this seem to have negative credibility.
I'm being equal opportunity here. If there was a massive push to label Trump as head of a child abuse blackmail ring and all the info came from hard-left rags and people known for supporting Clinton I'd be just as skeptical.