Having lots of money earned does not make a person bad.

They never said that. So maybe you're disagreeing with their reasoning because you don't know what it is.

They say billionaires are bad because they have a lot of money and don't use it to help people. This isn't even talking about billionaire who engage in actually/actively morally wrong deeds to acquire money.

If you produce a product so excellent that consumers give you 1 billion dollars ($1.000.000.000) in pure profit, there would be no problem if you kept a nest egg to ensure your livelihood and then used the rest to provide aid where it's needed. You would still be a bad person for sitting on it, instead of spreading it to help people that aren't well off. A person can live very well on $300K pretty much anywhere in the world: that means $999,700,000 is not materially improving your life and you are hoarding it for no good reason.

The only thing Newell is reported to have spent money on is stuff for himself and maybe the people close to him. He withholds the billions of dollars he owns from poor people he could help but won't. What is the worth in being a leech to society?