As a work-from-home dad with a very flexible schedule, I spend quite a bit of time at the park during work hours. My experience is closer to yours than most others in this thread. I find the moms/nannies/grandparents quite welcoming and friendly. Occasionally a topic of conversation will come up that may be a bit awkward, but otherwise I don't feel that I'm treated much differently. I certainly have never perceived that anyone felt threatened by my presence.
I'm not sure what would account for the difference. I live just a few miles from FB headquarters and am in the same demographic as OP.
I'm in the same situation... gotta love doing the bulk of your work before 8am or after 8pm (sometimes both in the same day) ;)
may be a bit awkward
Usually more than a bit awkward as they talk about trying to have more kids or women hygiene... that is when I just pretend my daughter needs some assistance and I walk off to "help" her.
I'm not sure what would account for the difference. I live just a few miles from FB headquarters and am in the same demographic as OP.