Actually, there should be a file “hosts” in that folder. It’s weird that it’s not there. But, anyways you have the “hosts~orig” file, which is a backup version of “hosts”, probably created during some system update.
I think you can just try to copy “hosts~orig” into a new file “hosts” in the same directory /private/etc/ (you’ll need admin rights for that). And then reboot your Mac.
Co-founder and lead developer at Soft8Soft.