There are a handful of policy issues where the implications of cosmopolitanism seem relatively clear: governments should give the interests of foreigners more weight in decisions that affect them
I think this is a slightly less clear-cut example than one might think. Traditionally most political philosophers who sought to justify the coercive power of the state have felt that the best or only way to do so was based on the special relationship between citizens and each other, and between citizens and a state. For example, the Fair Play argument given in various forms by Rawls (1971), Arneson (1982), Dagger (1997) and Klosko (2005), is based on the immorality of ‘free riding’, which isn’t really applicable to foreign aid. Dworkin (1986) and Horton (2006)’s argument from associative duties is similar in this regard. And clearly any conception based on consent will be local. I realise there are plenty of examples of philosophers who disagree with this and side with you, but my impression of the literature is that the localist side is dominant—and certainly not negligible. Perhaps as individuals our positive duties are cosmopolitan, but states are rightfully partial.
It might be a good way of explaining ourselves to social justice warriors. But a rather poor way of explaining ourselves to those who are triggered by social justice. Given that I expect that conservatives are under-represented among EAs, I think we should probably avoid going out of our way to alienate them any further.