The diversity you're talking about uses the definition everyone is familiar with from English.
The diversity Black Lives Matter is talking about is a technical term with the definition coming from Critical Race Theory, which defines whites as the least diverse categorically due to historically injustices against BIPOC folx.
> The idea of focusing diversity isn't at odds with focusing on competence
It is explicitly such, as stated by the movement you defend.
In that light, these are classic reads on the topic (copy pasting another comment):
[1] Why are There so Few Female Computer Scientists (Ellen Spertus, 1991)
https://dspace.mit.edu/handle/1721.1/7040
[2] How to Encourage Women in Linux (Val Henson, 2002)
https://tldp.org/HOWTO/Encourage-Women-Linux-HOWTO/
[3] What Happens to Us Does Not Happen to Most of You (Kathryn S. McKinley, 2018)
https://www.sigarch.org/what-happens-to-us-does-not-happen-t...
[4] Unlocking the Clubhouse: Women in Computing (Jane Margolis and Allan Fisher, 2001)
https://www.amazon.com/Unlocking-Clubhouse-Women-Computing-P...
[5] The Elephant in the Valley (by Michele Madansky and Trae Vassallo, 2015)
https://www.elephantinthevalley.com/
Also the news of RMS coming back seems to have been hidden from even FSF members.
https://twitter.com/fsf/status/1374399897558917128