Air carrier pilot landing Runway 2 at MSY reported another air carrier conducting a go around from Runway 11 passed 800 ft. over them at night.

Narrative

The Captain was PF (Pilot Flying) and I was PM (Pilot Monitoring). We were cleared to land on Runway 2 and another 121 aircraft was cleared to land on Runway 11. At about three miles from the threshold; we noticed that the other aircraft was about two miles from their threshold; whilst another aircraft was still on Runway 11. We noticed a potential conflict if we both needed to go around. At about 500 ft. the other aircraft was told to go around by ATC; due to traffic; still on the Runway 11. They had to climb through our altitude and when we were touching down they were barely 800 feet above our altitude. If we needed to go around; there would definitely have been some drastic maneuvering in order to avoid them. I queried ATC if landing both runways was a common occurrence and they said that it's legal to land both runways simultaneously because they actually don't cross. If you look at the airport diagram it appears to be only about 50 ft. separation between the crossing runways; so technically they don't cross. This practice seemed very unsafe to both the Captain and myself. What's legal doesn't equal safe in this case.