EDIT: MichaelStJules pointed out that I'm mixing up extinction risks (narrower term) with existential risks (broader term). I've edited the post to fix this.
I think a major implication of longtermism is that "we should care far more about problems which will cause suffering to many generations, or problems that will deprive many generations of pleasure".
But if like me, you accept Benatar's argument on the asymmetry of suffering and pleasure, i.e, that a lack of pleasure isn't a bad thing if no one is around to miss it, then the extinction component of an existential risk isn't a problem, since depriving many generations of pleasure by preventing them from existing in the first place isn't a bad thing.
However, many extinction risks are "progressive" in the sense that they will cause suffering for many generations before causing extinction, so they would still be a cause for concern. But the fact that they could cause extinction wouldn't really be relevant.
On the other hand, some extinction risks that EAs are concerned about could only affect a small number of generations (eg - very large asteroids), and could almost entirely be ignored in comparison to issues which could plague many generations.
I think a reasonable amount of people agree with Benatar, because I think most people don't see depriving an individual of pleasure by preventing them from existing as a 'con' of contraception.
So I think some people could benefit from thinking harder about whether they see extinction prevention as a priority in light of Benatar's argument.