Why is 'rich billionaire has uninformed or possibly self interested opinions' newsworthy
Plus, there is obviously an argument to be made that he has had a negative overall influence on the world & therefore shouldn't be trusted.
That is not only not obvious, but - even with his philanthropy efforts alone, the opposite would be obvious.
It's just that Bill Gates is legendary for the amounts he reads and his recall ability, and his contributions to many topics outside of just managing MS (state of the art algorithms, erradictinc malaria, nuclear energy etc). I thought everyone knew this, but apparently not. So you can see how funny it is when a random guy on HN says "just because he's a billionaire" :D
First you said "Just because Bill Gates is a billionaire, doesn't mean he knows what he's talking about"
Now that you've learned that most likely he DOES know what he's talking about, you changed your argument to "Other people think other things, so it's uninteresting" (What? WE're not talking about random people here.)
Lets just say it: you already arrived at the conclusion you want, now you're grasping for arguments to support it.