I'd say the assumption there is no Xenu is required to truely understand Ron Hubbard's motivations. You may think this is a "negative" assumption but really 786 - do you think you can have a meaningful discussion about Scientology AND assume there is a Xenu???
You are not assuming Xenu exists but rather the possiblity that he does- then you go about using logical, reasonable arguments against Xenu- once you get through that- then you can attack other tenets of scientology. This is the approach you should take to have any credence to what you are saying. Otherwise it is basically crap... (from the logical perspective)
Also yes you still can have meaningful discussions about Scientology even if you assume Xenu exists- your meaningful discussion would be about the nature of Xenu and otherwise something related to the tenets of scientology- which can still be meaningful
I think there are a lot of interesting things that can be gleaned and learned about both the Human Condition and the people who take advantage of it but stepping back and recognizing that Xenu is not real discussing how societies is affected by thinking there is a Xenu, why million of people worship Xenu (many ex-Muslims become Scientologist - I happen to have known one [although she quite eventually but she knows many Muslims who still do worship Xenu and pretend to be Muslims during the day]).
If you feel you are qualified enough to think about the motives of someone then be my guest- because I don't have those qualifications because the likelihood that someone who had no chance of winning, was being persecuted, was also close to death due to starvation as you possibly can would have motives other than truly believing what he was saying- or he could be crazy- but then talking about motives would be a pointless discussion. I don't know if the founder of Scientology went through such troubles but founders of other religions have.
These are interesting questions that can really only be discussed by first assuming HEY there is no Xenu.
They can be interesting questions if only you knew how to ask them and how to build an argument.
The exact same is true of Mohammad, Allah and Islam.
True after you consider what I said above.
Lets forget Xenu and everything else. Let me give you the taste of your own medicine:
Lets assume that Michael (You) were completely lying.
This means: [I don't mean this, but the following is an exaggerated example of what you are
essentially doing]
"You are a deceiver and the worker of devil, and you will rot in hell for eternity, and also your motives are to turn everyone to a non-believer so that they can be your buddies in hell. Because you can't live with anyone going to heaven or live in bliss. You want everything to be a deceiver. You want all husbands to cheat on their wives and all wives to cheat on their husbands. You are the starter of fights. You don't want peace. You want suicide bombers to kill little children. You want children pornography to be available on main street. You want everyone to die a painful death. You want to destroy the environment. You want everyone who disagrees with you to die. You are basically a sadistic lunatic! You're going to burn in hell with all your comrades. All Hail Xenu!"
[All of the above should be logical if everything you say is a lie. If you said you want peace that means you want warfare... and so on]
Is the above interesting? Perhaps.
Is it meaningful in anyway? No
What does it say? Whoever said this was basically expressing his beliefs
Does this have any meaningful logic? No
Is this called intelligent discussion? No
What would this be called? Ranting...
If even this doesn't get through to you then you need to pray to Xenu
Peace be unto you