why name this movie: Resident Evil?

Yeah, good point. It’s just marketing is what it is. But yeah, Biohazard would’ve been more appropriate name for sure and would’ve sold enough too as a title. Since that’s how the game is named in Japan in the first place.

I am sure Sony Pictures did all sorts of surveys and tests to see what their test public reacted with better: BioHazard or Resident Evil.

My guess is since a lot of people in the US say "brb bio" when playing online games, they may think of the word 'Bio' as toilet or bathroom. "Toilet Hazard" or "Bathroom Hazard" doesn't really fit well.

Resident Evil refers to the Umbrella Corporation and its despicable acts throughout each movie in this series, and actually fits well.

It was originally going to be titled Resident Evil: Ground Zero, but that was changed after the 9/11 attacks.