Why patriotic hymns do not belong at Mass

Today, 27 May 2018, is Trinity Sunday.  Mass was, to put in mildly, beautiful.  All except the closing hymn.  The jingoistic "America the beautiful".  Please relax, I am not bashing the song, America (I am, after all, American), or soldiers.  In fact, the Bible exhorts us the be soldiers for Christ (2 Tim 2), and both my maternal and paternal grandfathers served in the military (my maternal grandfather largely raised me),  I guess my problem is, is that we're not there for patriotism and honouring our soldiers, though those are good things in and of themselves,  This is an example of putting man before God.  The song was sung to honour, not God, but America.  I know hymns don't have to be about God (National anthems can also be called hymns).  Something about it, seems, out of place.  Again, I mean no disrespect toward veterans (although I am very critical when someone automatically assumes a veteran is heroic, that is usually true, but the inverse is too often true).  Another thing is this, if the song was to honour the veterans, why didn't they play it TOMORROW at Mass, instead of the closing hymn today?  To me, that kind of cheapens not only the song, but is really disrespectful to why we're there.  It is the CATHOLIC Church, not the American church, not the veterans church, but a church for all people, in all places, at all times.  Today was supposed to be about God, not veterans.  Honour our veterans, honour them everyday, but not at the expense of why we're at church.