That was a nasty, unemphatic thing of the friend to say. Birth is for many a scary, intimate time and for some, part of coping is having other women for support.
I recommend birth plans be as simple as possible rather than the long every little thing often found online, because much of those include things that will mostly out of our hands. Focusing on the essential information that could affect the labour and the most important preferences for wellbeing makes it easier to talk about - I had a great conversation about mine with my last labour. If having a female midwife fits that for her, I'd say go for it. Something like "I'd prefer a female midwife whenever possible" is entirely understandable. In a non-emergency situation, that might involve waiting and most of us get that in an emergency, we may need whoever is available.
It was discussed after my spouse had really had kidney stones and was getting a procedure to check what his preferences were and he didn't have any, but I can imagine some men being uncomfortable enough getting a camera shoved up their dicks that they might prefer another guy doing it. I wouldn't call them sexist - they're not questioning the competency, it's just scary and more intimate than most other medical procedures.
Yes she's a bigot for only wanting a female midwife. It's no different to her only wanting a white doctor or only wanting a male plumber.
Might be odd, but I have no preference when it comes to health care professionals, but I would greatly prefer a woman plumber if it was easy to search for one. Might make me a bad person (I don't particularly think I'm a good one), but I find having a male stranger in my house if I'm by myself or just with my younger kids way more intimidating than if I'm in a hospital, but I've had a range of awesome to violent women HCPs and take my own support whenever I can (which I said on my last birth plan - 'I'm scared being here due to previous medical abuse', and listed a few things that helped me cope) so I'm equally nervous of all of them.