As much as we want to take every fake site down, Forge is not supported by a massive corporation with the funding and connections that such an endeavor would require.
Sadly the best we can do is try to educate everyone about the dangers of these fake sites, and on that note I highly recommend you check out the StopModReposts project, Forge is not affiliated with them but so far they are doing a good job of creating a list of sites that rehost mods without permission and they have a browser extension that will alert you when you visit a site on that list.