Nationalism switches from being progressive to being reactionary when it is used to justify support for colonizers and imperialists.
Which indeed can happen and has. National groups who were once oppressed can simply become the oppressor. Begin their own colonization and imperialism using historical ethnic grievance as justification. You have brought up an example of one.
One reason nationalism is not like the other forms of identity, gender/sex or LGBT, is that of the capacity to mutate in this way. The idea of, say, people within the LGBT forming some kind of imperial force against straight cis people is absurd for a reason.
Further, for my own personal critique being an atheist, those other examples do not have united religious or spiritual associations. I do not want the religious unifying as a practical matter as a leftist and anti-theist.