I can throw in just a few observations, since I need more time to think about Crisi's good points.
1. Those are only verses in the New Testament. This confirms that only Christians will have that belief.
2. I think that John uses the correct language. "Lust of the flesh... of the eyes, etc." Indeed, that's a wrong direction that flesh, eyes, etc., can take. If there is lust, it should be made holy and directed only to our other half. It might be something we don't need, but surely will add something that I would not define bad, in a proper relation. So, we must see the context.
3. Romans is the colliding point for me. To understand it better, I need to go to my usual linguistic research. I found a nice page with the interlinear Bible: http://interlinearbible.org/romans/8-13.htm We have only the original greek, because the Hebrew was lost (it seems it was recently found in the Qumran scrolls, I think, but you cannot find it on websites yet). So, the literal translation should be "If however by the Spirit the deeds of the body you put to death you will live". Note: "deeds" in greek is "praxis", which is also the same English word. To me, it seems like saying: If you annull your daily cores actions (and dedicate yourself to holy actions instead), you will live. It seems like indicating: find time to read the Bible and make holy deeds. It makes more sense to me rather than saying: "Mortify the deeds of the body" - meaning to make afflictions.
4. All the verses seem to promote just the concept of "untying the knots (bonding) of the wordly things and tying the knots of the holy things".
5. I do not exclude the practice of affliction, which I sometimes do with cinder. So, it does have some value. I don't use the cilice or tools like that, however
Just my thoughts