OVKTD:
All those quotes address only whether or not R’ Hirsch’s Torah im derech eretz was intended solely for his generation (although I’m fairly certain that there is some disagreement over that). However, that does not mean that adopting secular culture or values is in any way an ideal situation. Torah im derech eretz refers only to secular knowledge (ie science, history, etc) not secular culture and ideals.
So my question stands: What reason is there to mix modernity (today’s secular culture, values and ideals) into Judaism?