IMHO, the issue is amperage. My Marquis Gold 7000 produces 54 amps of current, and the AC compressors need about 25 amps each to engage (then less at steady state). Once running, my genny can handle both roof AC units and a small TV for the grandchildren. If the system is overloaded it will pop circuit breakers on the genny (1-30 amp and 1-20 amp), but hopefully not brown-out any components.
BTW - the shore power needs for motor coaches are slightly different, as, for example, my rig was designed as a 30-amp connection to shore power. Working around 30-amp limits requires its own approach to the wiring of AC connections to get them both to work from camp power panels.