I am sure some people do have a problem with it regardless of faith or lack thereof. I am questioning your assertion that 'people have said it is oppressive while simultaneously no one has said anything negative about it'
Yes, I'm sure some imaginary people that you have never seen nor met have a problem with it.
Whose believing in things without evidence, now?

If its important enough for some to bring up, this implies it is a problem, doesn't it? It goes without saying that people who voice concerns about such a thing view it to be a problem worth mentioning.
Hence your point is pretty pointless, dude.

I didn't deviate far off topic. 
If they can't do that, they're really not worth it.
Furthermore...as someone who's not got a raging libido, I'd be concered that I would make this person feel dissatisfied as I would not be hopping into bed on the second, third, fourth date.
Though I suppose I wouldn't need to if they're sleeping with someone else.
Just no! FWB must stop! 
Just stop as soon as you decide you're going to chase someone else and pursue an emotional attachment. Respect the people involved.