I have missed that, and I am not sure of the context.
As I understand it support for the right to self-determination should be unconditional, up to an including the right to secession and independence. Whether it is progressive to encourage people to exercise that right is another matter.
E.g in marxist terms the right of Quebec to be independent from Canada should be unconditional, but progressive people in both parts of Canada might or might not argue for the right to be exercised in that way.
An independent Kosova would have economic problems on its own, and natural communications with Albania are not good.
But were you making a different point?
Chris