Hateful or not the video does feed the notion that homosexuality is a greater "sin" than heterosexual relations outside of marriage. I note no video has been produced to suggest how to explain to a child why men and women living together outside of marriage is wrong. No other forms of sexual relationships unacceptable to Witnesses were brought up or used to provide a comparative equality of sin in Jehovah's eyes.
Worse still is giving a young kid the black and white message that gay people can change. Of course this means celibacy rather than some "cure" but that is not even hinted at nor is it even really within the comprehension of such a young child. To them, through this video, "gay" is a choice that an be changed.
I agree in principle with Cofty's argument regarding the risk of over egging the moral outrage however please also let's not accidentally mitigate the pernicious underlying message in this video that gays are not welcome in Jehovah's organisation or in his new world of cuddly lions. It is feeding stereotypes and forming a pattern of thought that will lead to predjuice and even outright hated.