Elaboration is more of a quantitative thing than qualitative, though. It's always possible to elaborate further, and there's no harm in asking to do so. And I found that his further elaboration was helpful:

"I could also clarify that BountySource is opt-out: by default they're accepting bounties for projects that did not agree to having a bounty program."

I originally assumed you had to register your project on BountySource, and they were just making it difficult to de-register something that had already been added.

Making this thing opt-out only, and apparently making opting out difficult, is really bad behavior, and I completely agree with his characterization.