The site is mostly quite nice, not my style, but certainly not bad. I have 2 or 3 times over the years, and not been particularly happy. What I'm trying to say is that from my experience Nexusmods is not a great site. I'm not going to repeat everything in the first post, but I will repeat that on Moddb, I could download a 1 gig Skyrim mod, without an account, at around 4-5 MB/s, which AFAIK is limited by my internet.

I'm not demanding that Nexusmods do this, I'm just saying they seem very stingy, and, for me at least, this ruins my experience with the site. However they could just cap download speeds for non-registered users, and most people would just get an account.

To me this doesn't seem like a very good reason, why can't they just count downloads from registered users? You might point out that less people would get accounts, and you would be right. We require all users to login to a Nexus Mods account when downloading to prevent abuse of our systems, to provide additional security and so we can reliably reward the mod authors on Nexus Mods via our Donation Points system (which relies on us being able to record accurate download statistics). They actually state their reason for it when you try to download something without being logged in:

Nexusmods recaptcha bypass