So, first, I went into pandemic prevention / mitigation and not AI risk, and I haven't been claiming here that AI risk needs more people. Compared to the median EA, I am less convinced that AI risk is where we should be putting the marginal person, though I do think it is still important and a good place for people who are well suited for it.
The main problem I see with AI risk is not that it is a small problem, or that there are too many people working on it, but that we don't really know how to make progress and historical attempts maybe have ended up making things worse.
Still, I think gradys' point above is a good one: the fraction of people working on making AI more capable is far far larger than the fraction working on making sure it reliably does what we want it to do even in unusual situations.