my parents raised me to appreciate simplicity and avoid greed and excess

LW's attitude seems like there's something more going on than just appreciating his own minimalist lifestyle. Dismissing GF's family's lifestyle outright as "toxic" and "damaging" is really concerning.

I want to say this is virtue signalling, but I sense a real undercurrent of envy and resentment here. One person's "simplicity" may actually mean "deprivation," and I have to wonder if LW might have felt deprived in some way growing up.