Simply put, repacking mods has caused trouble every time it's happened, licenses are not honored, old versions are used, they are not updated. This causes trouble for modders as players using these modpacks come to them for support, often for issues that are caused by the repacker. This also leaves old mods in circulation as part of these packs, the packs might become popular but again they cause trouble for modders, asked to provide support for things they already fixed but will clash