In my opinion it is not a problem at all. But some want to see it as a problem. I wonder if the same people consider underrepresentation of females in garbage disposal or plumbing as a problem too.
Sex underrepresentation isn’t a problem itself. It’s a potential source of problems—if you saw some statistical outlier while profiling software, you’d pay more attention to it and verify whether it’s causing issues. Homogeneity of any kind tends to create bias and brittleness.
When you ask women why they don’t program, there’s a mix of normal things like “I don’t find it interesting” and “I prefer X”; but many also say “I don’t feel welcome”, and I would like to improve on that. In the same way, when you ask black Americans why they don’t program, a disturbing number say things like “I never had access to a computer”.