The words of Born in the USA are pretty unambiguous, and they against everything Reagan represented. Take a look at them here . Not a trace of irony to be interpreted or re-interpreted.

With the Strawbs song it's a bit different. Plenty of room for reading it either way, as a straight affirmation of union membership and industrial action, or as a heavy ironical attack on those things.

Have a look at the words here - on the "Activism and protest song lyrics page" of "the Ontario Coalition Against Poverty".   The intentions of a song writer or of particular performers do not pin down a song to whatever meaning they might have had in their heads. Songs can take on a life of their own.