The thing is; unlike many ninjas which come with free to cast on both sides (Gnw Orochi, Kimono Konan, Normal Kushina, Chinese Style Neji) with different results when using it on offensively (on enemy) defensively (on teammates) Kurenai's ult is meant to be used on enemies and shouldn't work on herself or teammates, because it's simply a debuff (immunity remove, chakra limiting, immobile)

It's definitely not the same w Ibiki as Ibiki is bound to enter under Torture state and it's written in the skill description. With Kurenai Summer, you can cast it on both sides even though it's a debuff and should be enemy-only.