Earlier quoted context omitted.
> We should have never allowed them What does this mean?
I think the person you're replying to meant that China should not have been allowed to join the World Trade Organisation without further requirements.
I think the hopes were that China would benefit from trade and developed its own industries in a largely decentralized fashion (which happened). What didn’t follow was the assumption that this would cause them to become less authoritarian and more democratic.
Quite the gamble in the end; I don’t think those responsible over many decades realized what the consequences would be for getting this wrong. They all were championed by equally blind stock-market driven CEOs who wanted cheap labor, low/no environmental laws, no unions, a helpful and competent government, and new large markets who didn’t already have lots of stuff.
The US has gotten terrible at long term vision, while China has nothing but long term vision and long term memory.