Because its free money they don't have to give back?
It really is a bitter pill to swallow for them to come back and ask for $1m so soon after their old kickstarter project. It's currently looking like they have tapped out their target market, as they are only trending towards 75% of their goal.
I have many reasons why I don't like the way they are approaching their project, and the way they are leveraging folks love of the Pathfinder IP to fleece the money out of them. This new kickstarter project pushes that over the edge for me, and I really hope they don't hit their funding goal. If they don't, they will still make the game (as you said, they have other investors), they just wouldn't have fleeced their community for millions of dollars to do so.
Also, its worth pointing out, they only intend this $1m to develop the next block up to beta. At that point, they will be doing another funding push, which may mean another kickstarter or similar crowdfleecing project.
Another thing that is worth pointing out. Their initial kickstarter project asked for $50k to make the tech demo. They got $300k. Apparently that has all been spent, in 6 months, with a lot of that going on "wages". Yes, the tech demo was done (although, it doesn't really show off much), but I'm not sure I would say its $300k worth heh.