A lot of interesting yes's and no's but still no answer as to why?
Okay firstly yes it does slope upwards on all A300, A310, A330 and A340 aircraft. No it's not a design fault and not specifically to house LD3's or to get the FA
's to push trolley's up hill.
It's a simple matter of space utilization. Sloping the floor upwards slightly utilizes the maximum available cabin width in that part of the aircraft.