I don't have a problem with the rest of your post, but I think that statement is going a little too far. God could make the new heaven and new earth and have no hell and had justice done another way. I think the problem with people not thinking that this is not a loving message is because they are blind to the need for their own redemption.
It's like a kid in a small town who is the best at basketball and thinks that he will get into the NBA without really having the skill or born-in talent, but his peers are all a little worse than he is, so why wouldn't he be able to? Until he finally gets to a tryout and realizes that good enough is such a high bar that he would never be able to get in with all the time and effort in the world.
All these reality shows illustrate this thinking nightly. You can see a person who is completely full of himself come face to face with failure and try to rationalize it in front of a camera. Self esteem programs do not make success, and neither does feeling like you are going to heaven make it so, but our culture is permeated with that idea.
Ahem... God could have done anything He wanted to. The fact remains that you have to live with the way He designed justice and the payment for it. If you live according to His rules, you have no choice but to accept that He created heaven as a reward and hell as punishment.