If temporarily increasing the concentration of women panelists contributes towards permanently reducing discrimination, then it's a net gain for humanity, even if it's a net loss for panels in the short term.
If everyone waits for the rest of society to change, it never will. Note that I'm not saying any one proposed solution is the right one, but it is an important discussion.
Just because you have good intentions does not mean that any random idea you put forth will achieve those good intentions.
There was a study performed on young students, concerning their perception of STEM fields. Most respondents indicated that "techie" people are all white males in lab coats, and that the respondent wouldn't fit in well with that group. (Sorry, I don't have a link to the study. But I know I saw it in the last 8-12 months)
If more women are publicly visible in tech fields, then young people's perception of techie people will swing away from "homogenous white male group" towards a heterogeneous group that is necessarily less discriminatory. This should cause a corresponding increase in enrollment by non-white non-males who would otherwise have been dissuaded from joining.