The Twitch/Curseforge app did not allow for modpacks to contain the optifine mod as it is only avalible for download on optifine.net. It would be great if there could be proper incorperation of Optifine while still allowing the creator to make money off it.
We welcome openly any creator to join CurseForge as home for their mods.
As mentioned in the comments, mods must receive permission to be included in modpacks and we will continue to honour Optifine's creator (and others) choice.
We do plan on reaching out and keeping in touch with various creators currently not on CurseForge to discuss collaborative options.