"I think it prooves that moisture goes through their cheap a##ed paint"
That's right, and some TSB in Dodge annals addresses the problem, sorta'. The TSB (technical service bulletin, which number I don't recall) says that in many cases where the owner has used aftermarket accesories such as bras, that stainless rocker cover stuff, or other things which cover the paint moisture will enter the clearcoat and be trapped. Apparently any sustained damp condition may do it as well, Their fix is to apply heat gun in the hopes that the bubbles and milky appearance will clear, and goes on to say that if that attempt fails repainting will be necessary.
As to whether there is warranty coverage: do a search on paint looking for posts by "illflem". He has successfully prevailed against DC in such a situation. Your dealers are giving you bull as they are fully aware of the paint issues with trucks of your years.
Our '98 truck has ruined paint below the beltline. It had that stainless rocker BS when we got it, and we removed it to find a mess. None of the usual body/paint shop fixes helped at all - mostly it got worse.