Oh yes, they want us but just as you said, they want us only so they can use us. They truly have yet to grasp the depths that we have gone for them, to try and help them.
There is no understanding them and how they see the world or how they choose to experience the world.
Yes, our Difficult Child want us to continue supporting them, they want to live their life on their terms but they expect mom and dad to pay for it but that's where we as the parents have the control, we don't have to support them, we have the power to say no.
Accepting their choice to live the way they want to and be the way they want to is not easy. It took me years. It took being burned over and over again.
In the rare times that I converse with my son and he goes into the pity party routine I can only be supportive to the extent that I tell him "I'm sorry you are having a difficult time, I'm sure you will work things out" Or if he has one his "gonna make a bunch of money" schemes, I just tell him I hope it works out for him.
This is not an easy journey we are on.
As for sounding angry, I would hope so. Anger is part of this. You can't get past a certain point unless you get angry. Without the anger I think parents are stuck in denial. They truly don't see how a Difficult Child can suck the life force right out of you, they just keep giving them money and doing their laundry.