Other mistake: When Carter is sitting in front of one of the small hatch-like doors around the time that they were climbing the ladder to escape from the rising water, one can clearly sea that the door is no more than twice the width of Carter (4 feet at most) yet the 45 foot shark about 10 to 12 feet wide seems to have no trouble squeezing through. (01:01:40 - 01:04:20)
Other mistake: Near the beginning of the film, Carter asks Tom how high the fences are, then he tells them to make them higher, and Scoggs confirmed they were raised, but you can see that the fences never get any higher.
Answer: They viewed her as a villain because it was her research that backfired and caused all of the chaos, even though none of it was intentional and it was a mistake. But audiences can be ruthless and unforgiving at times. However, the ending did feel like a cheap cop-out that created more plot holes. And many do feel she should have survived and completed her character arc. I don't know why they never offered the ending as a bonus feature on the DVD, but fans started a petition on the Change site calling for Warner to release the original ending. Thomas Jane is on board as well, as he's promoting it on his Instagram account. So that's probably the best way to get Warner's attention if you want to see the original ending.