Earlier quoted context omitted.
In theory, the vulnerability was always there, and it's better to find out than not find out. In practice, how much effort it is to find vulnerabilities matters a lot. We're in a time where things that used to be quite hard are now easy and the rate of discovery will change. This rate of discovery matters a lot -- for OSS maintainer burnout if nothing else.
It matters in a positive sense; it's a thing that enables you to make some predictions about the state of the world tomorrow. It does not matter in a normative sense; OSS maintainer burnout is strictly a less important concern than software security, which is an externality of software development.
And if the capacity is overshot (which I believe is happening as we speak), users end up in extended states of being insecure.
I'm also one of the unwashed rabble who believes there is a large practical difference between a vulnerability that exists but isn't found and one that is widely known and exploitable.