I do feel everyone is equal in value. Possibly equally worthless depending on how you view humanity's place in the overall universal timescale.
Whenever you look at someone else and think they are being arrogant or self important...likely it is time to take a step back and think about why it is OK to think that they should not feel that way. Maybe they have good reason that day to feel self important :) Take it as a good opportunity to take a good look inside and realize...overall...it doesn't matter how other people view themselves.
That quote is often associated with Bill Gates in the context of running a charity. In that case it has merit. But on a personal level it makes no sense, at least literally.
The fact that the response to that is discussing money should be a red flag to you.
You can be good to your neighbors without giving anything but a smile and a kind word.
That would be as silly as that criticism of equality. I'm still unsure how we go from 'All people are equal' to 'Are they? I don't see you sacrificing <arbitrary amount of money> to help your fellow man.'
What was the point of that remark? Persons may be said to be of equal dignity, but no two people are ever equal, in value or otherwise. But what does that have to do with anything in this context? Are you reading things in? The OP was not making any point about rank, only haughty behavior which has no place no matter who you are.