You seem to have an extremely weird definition of "xenophobia".
Let's review it: "fear and hatred of strangers or foreigners or of anything that is strange or foreign".
And let's compare that with what you wrote:
1. homogenous
Nope. No fear or hatred there.
2. "IMHO, a lack of diversity certainly signals that something is going on."
"Certainly" is certainly wrong. It might signal that something is going on, and it certainly doesn't give any evidence what that "something" is.
Have you ever considered that the "fear and hatred" might be going the other way? Just the terms geek, nerd and hacker have highly negative connotations in the wider public.
3. "You might find the term "xenophobia" too strong"
It's not "too strong", it's completely wrong, victim blaming a group that is being shunned for being shunned.
4. "very palpable jock-nerd atmosphere that will turn off many folks"
And now you're completely off into the weeds. Doing things that causes other people to shun you is not "xenophobic" by the people being shunned. If anything, it's the other way around.
Let's review it: "fear and hatred of strangers or foreigners or of anything that is strange or foreign".
And let's compare that with what you wrote:
1. homogenous
Nope. No fear or hatred there.
2. "IMHO, a lack of diversity certainly signals that something is going on."
"Certainly" is certainly wrong. It might signal that something is going on, and it certainly doesn't give any evidence what that "something" is.
Have you ever considered that the "fear and hatred" might be going the other way? Just the terms geek, nerd and hacker have highly negative connotations in the wider public.
3. "You might find the term "xenophobia" too strong"
It's not "too strong", it's completely wrong, victim blaming a group that is being shunned for being shunned.
4. "very palpable jock-nerd atmosphere that will turn off many folks"
And now you're completely off into the weeds. Doing things that causes other people to shun you is not "xenophobic" by the people being shunned. If anything, it's the other way around.