Not a capture but an ideological generational shift. The ACLU has long had a very liberal lean, not necessarily in a bad way, and their ideology being based on some non-partisan ideals in the past. As the political nature shifts and the polarization of politics increased they naturally shifted more partisan as they never bothered to seek "political diversity" within their ranks.

Go to any kind of DEI meeting and mention that we should adjust hiring policies to better reflect the political party affiliation and they'll lose their shit. But isn't the whole benefit of diversify to bring in a wealth of different viewpoints and not necessarily different body types? After all one could argue that in an American context, some white male born and raised in Sweden is the more diverse candidate than some black female born and raised in a well off liberal American city? After all his background is more different. To argue for one over the other in terms of how they look, could be described as a kind of fetishizing no?