I know the company and I know about tptacek from HN, even a friend worked there a few years ago. I just wanted to understand if they were in some new specialized niche.
Sure. I'm just explaining how someone could conclude that hiring for a software security team is actually harder than hiring for a typical startup; the skills requirements are close to a superset.
Could it be that the specialization you are working with ends up actually be a benefit with regards to finding new hires?
From my perspective, I'm probably not going to go out of my way to apply to a typical startup unless there is some reason to believe the renumeration is remarkable. However, I might be interested in applying to a company like yours as a challenge to myself.
That happens. For example, to be a low level 3d engine programmer is a quite specific skill, yet because of the nature of the games industry, such people don't get paid as much as your average full stack web developer.
