Relative deprivation occurs when people learn about other cultures where people have access to greater wealth. In the information age I don't think this is avoidable even if we stop trading with each other.

> Relative deprivation occurs when people learn about other cultures where people have access to greater wealth

That's one of many places where it occurs, yes (it also happens locally.) Trade can exacerbate it, because even superficially mutually beneficial trade doesn't advance the wealth on both sides equally, and the degree of difference in material position, not merely it's binary existence or not, is a key factor in the magnitude of the resulting disutility.

I can see how this theoretically might be the case, but I am unpersuaded that lifting a billion people out of abject poverty in east asia was actually bad for them because a bunch of westerners got relatively richer in the transaction as well.

I suppose this is a matter of judgement though and not an objective fact so to each their own.

> but I am unpersuaded that lifting a billion people out of abject poverty in east asia was actually bad for them because a bunch of westerners got relatively richer in the transaction as well.

That's a nice strawman you've set up, but no one in the discussion actually claimed that.