> Every application has those bugs; on a software pentest, we'd sev:lo them.

Every application has a bug that can bring the whole application down for every user without owning a botnet? That comes often with a significant business cost, if someone exploits it. Many companies take them seriously. I have reported many as high and business has agreed. Not with HackerOne thought. If there is a bug where someone can make your whole product down with a single laptop isn't really something you can just ignore.