1) The obvious reason is that she sided with Rourke and helped him steal the Heart of Atlantis.
2) She didn't seem to care whatsoever that stealing the Crystal would kill off the entire Atlantean civilization. "Knowing that, I'd double the price."
3) The fact that Kida became the Crystal didn't seem to affect her very much. If Kida and the Crystal were one, then she'd simply take Kida back to the surface and sell her to the highest bidder.
4) An incident in the Crystal Chamber caught my attention: When she first lays eyes on the Crystal and the protective King Stones, Kida is overwhelmed and falls to her knees in prayer. Rourke then tells Milo to tell Kida to "wrap it up." Milo is greatly offended and clearly feels very bad for Kida. Helga smirks and rolls her eyes. She clearly feels the whole thing is funny.
5) On the Gyro-Evac she shot at the Atlantean crusaders! I saw her take shots at Vinny, Milo, and a few random Atlanteans to name a few.
6) She held a gun to Kida!
1) Let's begin at the beginning. First of all, Helga brought Milo to meet Mr. Whitmore. If she hadn't done that, the movie wouldn't have happened. Helga was the catalyst, shall we say.
2) She keeps the crew in line. She makes sure that they do what they are supposed to when they are supposed to, and makes sure that they don't do what they're not supposed to. "All right, people, let's get moving. No, Vinny! Audrey takes the oiler. You know the rules. You stay 50 feet away from those trucks at all times!"
3) She gets everybody off the Ulysses during the attack of the Leviathan and she steers them into the air pocket that leads to Atlantis.
4) She knows how to handle herself in a crisis. For instance, the Leviathan: "Load the torpedo bays! Subpod crew- battle stations!" Or the burning campsite: "Don't panic! Get some water on that fire!"
5) Her conscience troubles her when she leans that there are still people living in Atlantis. She says, "Commander, there were not supposed to be people here. This changes everything."
6) She seriously looks freaked out when Kida bonds with the Heart of Atlantis in the Crystal Chamber.
7) She blasts the Gyro-Evac with her flare gun, preventing Rourke from escaping with the Crystallized Kida and helping Milo destroy Rourke.
Well, I left it up for the populace to decide by putting it to a poll. Here were the results!
Personally, I agree with the general majority by saying she's a heroine, due to reason number seven: She blasted the Gyro-Evac. I seriously think that at the end she had a change of heart, and realized what a mistake she made. It may have been to late for her, but she still was able to at least stop Rourke from escaping. Either way, I think we can all agree that Helga kicked some butt!