Thanks for the information. I didn't realize that Colossus is not a new modpack, it's a very old one. It's asking me to download other older mods that do not even exist, so it's not Optifine's fault or problem, it's AT Launcher's and the fault of all these older modpacks on the various sites.
And so it goes in our "legal" world. Bah, humbug, I don't like lawyers at all.