There are limited resources on this planet. You can't have massive population growth with 10 people holding as much leverage to consume those limited resources as nearly half of the population and still have a balanced system. We can talk about systems that exist in non-equilibrium states but massive imbalance when it comes to the allocation of finite resources coupled with population growth is equivalent to massive suffering.

Evidence that these 10 people are actually "consuming" as much as the 3.1 billion?

I don't think they are. Not by many orders of magnitude.

What "limited resources" are billionaires hoarding compared to the everyone else?

Political influence. Speech. Representation. We revolted about something similar a few hundred years ago.