Sex in shared living spaces

[MyTurn2Raise]

OK...so that post about the guy catching his roommate and roommate's gf together got me thinking....

I've shared apartments with numerous people (all men) in the past and nearly all of them stated that sex with females in shared spaces (living room couch, bathrooms, office, kitchen table, balcony, etc) was forbidden.

I, of course, never acknowledged the existence of these rules. I figured if my roommates had the chance to nail a girl on the kitchen counter, they would've done it too.

I remember one roommate in particular was pissed because he correctly assumed that my lady friend and I had sex in the apartment's 'black room,' a room painted completely black with some posters in it for tripping. Another was pissed because he correctly assumed that I was with a lady in the shower that we all shared.

My questions:
Do any men actually respect these 'rules'?
Are my roommates correct in getting pissy over these situations?
Am I a dick based on these instances?
If so, why do I not feel bad in the least?