The link on Yobits for Waves has been available prior to IOUs going live, it just redircted to Lisk.
1. Devs should make official posts/tweets about not supporting it. This was done by Lisk.
2. Calling people idiots and retards because they trade there (I don't personally) is uncalled for. They are willing to take a risk on the exchange. It's their money. What's important is item 1.
3. If this was a surprise to anyone, including devs, I don't know what to tell you.
4. IOUs for every popular ICO will happen. It's a matter of devs and the community distancing themselves if they are uncomfortable.
Let's minimize the drama and name calling. So much to do in the coming weeks.