First you say it's going to hurt the poor, but you haven't provided the evidence as to how. It's already been stated that people who are below the poverty line, and even those up to 400% above the poverty line, will receive a tax break to help them purchase insurance. And for those who still can't afford it, there is a hardship grant that will still allow them to get insurance through the public option.
The mandate is what is required in order for the insurance companies to be able to provide insurance to everyone at affordable rates. Again, this whole process is already working with Romneycare.
Number 17 in your link and your own post that says $400 for a person with an AGI of 40,000. I would hardly call $40,000 living large.
Based on 2011 a single individual who has an AGI of $40,000, assuming all W-2 wages, has an approximate tax of 3,824. Which is 9.56% of AGI. Assuming your information is correct and a person with an AGI of $40,000 would pay $400 in a new 'tax', that percent goes up to 10.56%. It seems to be that the new $400 tax will hurt them more than it should.
The mandate is not required for that, the mandate was put in to kiss up to the insurance companies for putting all the new regulations on them. Good regulations I might add. Pretty much saying here are all these new guidelines you have to follow, but don't worry we will make sure you have more consumers. The worst thing that could have happened to insurance companies was the individual mandate being stuck down and the rest being kept.
If the whole law got thrown out, then it would have been business as usual.
With the main parts being held constitutional, they have all these new regulations, but they will also get a larger customer base because of it.
If the mandate was struck down and the rest held constitutional, then they would have all these new tough regulations on them without the huge increase in consumer base. On a side note, this is the way I thought the court would rule, so I shorted Aetna based on that. Turns out I was wrong, but still made good money on the short.