Mods to break between versions, which is annoying. However, the sites are usually MCForum or Curse, neither of which are especially shady, and I've never seen

Mods to break between versions, which is annoying. However, the sites are usually MCForum or Curse, neither of which are especially shady, and I've never seen a mod packaged as an exe by its creator. You're probably looking at the cites that host a collection of mods from other sources, which are about as shady as their software equivalents: sites like cnet, etc.