I think there are two ways to look at the quoted statement. Is person A with 2 years of professional software development experience and a 2 year gap about the same [on average across a large population] as person B who has 2 years professional software development experience and no gap? Person B is slightly more valued by virtue of recency of experience, but 3 months from now, once the rust is knocked off person A, I'd expect them to be basically the same so I'd value them the same in hiring.

Now, is person C who has 4 years of software development experience, no gap, more skilled and capable at software development than person A who has 2 years of software experience and then a 2 year gap or person B who has 2 years and no gap? Absolutely, and I'd expect C to be quite rationally valued more highly in the software development market. Person C has twice as much directly relevant experience at a time in career where the curve is still rising quickly.

I'm pretty biased, but it would depend on the role.

Thinking that parenting is not "experience", or that it has no commercial relevance is (in my opinion) a mistake.

Many roles, I suspect a candidate with 4 years of SWE and 4 years of parenting could be a more valuable team member than a candidate with 8 years of just SWE. Parenting does not universally develop emotional maturity and wider perspectives, but I believe there's a correlation.

Disclaimer: Of course, individual differences swamp any other factor, so always take each person as they come.