Advocacy involves 1) understanding your target audience and 2) making an appeal to them.

If the composition of your organization does not reflect the composition of your target audience then both of those tasks become a little harder. This is not specific to the FSF, many organizations hire at least a few people who match their target demographics to do things like research, marketing, messaging, and outreach.

Why is it not?

No one was, in the remotest sense, being ageist, sexist, or racist above… seeking to widen the appeal of something beyond an old white male audience isn’t, in any way, to anyone but an absolute dimwit, seeking to discriminate against that old white male audience.

Or, in other words that might make sense to a programmer:

   assert (old && white && male) + (!old || !white || !male) >= (old && white && male)