Simple: Because it can and will be abused, unless they manually verify them first. Those patches do require the paid mod, after all.
Other than that, you'll have the legal issue, as Nexus has little (or no) control concerning permissions of these mods. And them being a “product”, this is a little different to other mods that are uploaded on a 3rd party site.
I do? Which point exactly is it?
And this is where you are fundamentally wrong. The implementation of paid mods already did harm the community. Treating them as normal, normalizes Bethesda's fancy business model. It's not even just the money issue, I already mentioned before. It's also the audacity, calling these mods “official content”. You won't believe, how many people are convinced, that these paid mods would be Bethesda content, and thus treat them superior to other mods, just because they are free. After years of work and support for free mods, this must be like a slap in the face.