John Beckett I agree with. I think his sermon can be best expressed into one word though. That word is respect.
I'm not entirely sure why John Halstead you are worried that the scientific method can't be used, or that Polytheists(hard, soft, squishy in the middle, or other various Pagans of squishiness) can't use healthy skepticism. I've seen plenty of Polytheists argue with you, and they manage to do so intelligently and use logic in the process. I think you are letting your fears from your days of Mormonism flow into your religious experience and feel if you aren't separate enough, you will fall into the Mormon trap that you feel is bad.
I think that John forgets that our Gods aren't the Mormon or Fundamentalist Christian God. None of the Gods I have encountered want obedience to the extent that I have seen in the Christian Fundamentalist circles. I think it might help if you got to know our Gods a bit better before being concerned about that trap.
Ok First off, I as a Devotional Polytheist, am not trying to prove my Gods are real seperate distinct individuals. I know they are. I know they are the same way that John I know you are John Halstead, midwestern attorney and sometimes Gadfly of Patheos(btw I'm more annoying then you, sticks out tongue lol). You and I can't be interchanged. Thus goes one of the arguments of Hard Polytheists about picking and choosing Gods.
Your other argument, that people won't feel as welcome in the big tent of Pagandom if you don't argue, I find confusing. Hard Polytheists aren't saying you can't be a Pagan. They are unequivocally saying you can't be my type of Polytheist if you believe or say x, or y, or z. If people don't feel comfy after encountering people who argue, it's not my problem. Paganism is largely a religion full of adults. It's not my job to hold peoples hands, in case their feelings get hurt. I would argue it's highly disrespectful to the seeker to expect that. You are expecting us to treat newbies like children, or experienced people like children. Not gonna happen.
I think you also forget that not everyone wants, desires, or wishes religion the way you do. I am a Polytheist because it isn't bland. I found the CUUPs way to be bland, Wicca(while not blandish, not as real as I liked) and Pantheism is bland. I want the full flavor and access to the spices to flavor my religion that I get out of Polytheism. See Mind of a Chef season 3 with Edward Lee on how I like my Polytheist food.