You didn't actually say you were building a fraternity. You said "I'm building a social club and support group for engineers/designers/product people, some wearing a second hat of founder/investor."
You mentioned fraternity only in this way: "Imagine something like a mini-fraternity (in only the good ways) with dinners, retreats, bonfires, product jam sessions, meditation, improv, basketball, whatever people want to do socially & professionally".
It should be clear you are not describing an attempt to make Silicon Valley "Animal House," except to those who are going out of their way to find problems. In my opinion you have nothing that needs apologizing for.
You mentioned fraternity only in this way: "Imagine something like a mini-fraternity (in only the good ways) with dinners, retreats, bonfires, product jam sessions, meditation, improv, basketball, whatever people want to do socially & professionally".
It should be clear you are not describing an attempt to make Silicon Valley "Animal House," except to those who are going out of their way to find problems. In my opinion you have nothing that needs apologizing for.