who said anything about dumping the solids at the campsite? i would bring my solids home with me and compost them at my house. i would never dump them out in the woods. ever.
i wouldn't dump a gallon of urine on a bush no. that could kill it, depending on it's size. do i think it's ok to dig a small hole away from vegetation and streams and dump a gallon of urine in it? yes. even according to leave no trace if you're camping in an area you can dig catholes or latrines. heck in colorado you can't even camp within 100 ft of a stream anyway. seriously if i'm tent camping for a week in one spot with someone else is it not just as good or better to dig a hole away from vegetation and pee in it than to pee all around on vegetation. part of leave no trace is not affecting vegetation.
of course it's not ok to leave 40lbs of poop at your site and no one ever suggested that.
yes i always haul my black and gray tanks to a legal dump station.