Not supporting custom events is pretty much the same as not supporting web components. What if you use a third party web component that has dozens of events? The goal should be interop with no additional plumbing required.
There was a time when React literally just didn't support web components, so I don't think that's really fair. Yes, it would be nice if it worked completely free, but if you're only listening to 2 or 3 events on a component, it is definitely a fair price to pay for being so bleeding edge.
