For me, as long as the game is consistent with its own rules it is fine.
This is a fantasy thing, nothing is "realistic" per se, but we do have a pretty well defined set of rules about what is realistic WITHIN the fantasy of the game. So when something breaks those rules, it sticks out and is frustrating. That is why it doesn't make sense for frogs to die while malignant cells do not. I frankly don't care because this is probably for balancing reasons and not a big deal. I mean you could also argue about which creatures should be airborne.
Anyhow, as long as everything in the game sticks to the logic of the game, I am not worried whether this could actually happen.
It is the same thing in a movie. I can set aside all my preconceived notions for a fantasy movie. And the movie can be really good. But if something in the movie breaks the fantasy's own logic, it pretty much ruins the movie because I can no longer suspend my belief.
Take Inception. No one is out there arguing that there is no such device that can hook dreamers together. No one. People are talking about what happened in the movie but no one is questioning the basic premise of being "unrealistic". We all know it isn't realistic but the movie did a pretty good job of sticking to its own logic.
I don't have a good example of a bad movie off hand but generally they break their own internal logic, which breaks your ability to set aside realism. Then you just think the movie sucks and question every aspect since they broke their own rules.
