When they say "makes negotiations harder" they're saying it from the position of "getting what we want out of the negotiations is harder" rather than from a neutral position. It's strictly one sided, negotiations are a means towards the US advancing its position. Everything is always a different means of the US advancing its position, the US has never contemplated not trying to "win", not trying to create a monopoly out of the entire world. To capitalists countries are companies and the progression of companies is consolidation into monopoly. That's what the nato camp ultimately is, a consolidation of 32 previously independent countries into 1. It continues to "expand" because it is ultimately trying to consolidate the entire planet into a monopoly. This is just how everything works when everything you look at is a market.