yeah idk what OP means about settlers this seems to have very little to do with settler-colonialism this is basic-becky social chauvinism a la the collapse of the second international and communist split due to the lack of will to stop WWI. These guys are openly (embarrassingly) direct descendants and inheritors of that exact legacy of the failure of the second international. These pro-war social chauvinist imperial unionists were being railed against by Lenin in Europe for supporting their nations imperialist war machine for the opportunist job security and benefits provided compared to other labor (or fighting at the front), at the expense of the international proletariat, by acting as collaborators of war. It's more a symptom of the dynamics of basic old-style imperialism than an internal settler-colonial relationship. Every European labor and communist parties had splits over this in the mid-late 1910s.

Social chauvinism like this occurs even without or in spite of any settler-colonial relationships, because it's a function of basic externalized imperialism not of an internal settler-colonialism, as was demonstrated historically by this occurring even in non-settler-colonies in 1900s Europe. There are reasons that unions are not sufficient for revolutionary societal change and are not inherently progressive even in non-settler-colonies; and a reason too that the ILA has a huge portion of its rank and file and chapter leadership that are black proles also still backing this to the hilt, because they benefit from imperial spoils the same in the context of the job and union itself; as as 'essential-for-empire workers,' they are inherently 'overvalued' (in the sense of when compared to the exchange value of labor-power for other workers, in the value they generate and their importance in 'keeping the machine' of imperialism running and all the downstream externalized contradictions from coming back to the mainland).

The way this is connected to settler colonialism is only distantly or indirectly, in that the expanse of empire, by being rooted in the initial primitive accumulation through settler colonialism, means the US empire could reach farther and out-compete other empires previously, meaning larger returns for a labor-aristocratic imperial-collaboration can expand to more people than for a poorer imperialist nation, and remain stably such due to the hegemonic power of global empire that these unionists facilitate; which completely obscures the settler-colonial relationship for these workers by dulling the contradiction to invisibility, by those contradictions being exported (through the imperialism, war, that they facilitate).

This shit would happen with or without settler-colonialism in an imperialist nation because it always did. And for these workers in particular the settler-colonial dynamic between them only might become relevant again in the sense OP is alluding to if those externalized imperial contradictions were reimported and the internal contradictions sharpened by those spoils of empire they all collaborate for shrinking to a smaller amount than could serve to buy all of them off like it currently does; and a struggle for "who got to remain in the empire's war machine" began between them. There are implicit social dynamics in a settler-colonial context like this but those have nothing to do with the existence of social chauvinism and unions supporting imperialism itself.