i like how you are thinking about this. I was fired once from a company that had mostly married guys with kids. The manager vaguely mentioned this to me. It's probably "discrimination" under some sort of law, but I like your framing better. 

He can see that  I didn't fit in and didn't enjoy working there, and it's not "because" of anything, it was just not a good fit!

getting fired however never feels good so, it's just hard to manage. I thought I was cool and could fit in with an office full of married straight men with kids!