Since you compare it to religious indoctrination: I wouldn't want my child to be indoctrinated into believing some religion, but I still want my children to learn about religion. Not because I think it's important, but because we live on a world where a lot of people DO consider that very important. We don't have to agree, but we should at least try to understand the people around us. The same way I don't think there is any harm in learning kids about trans people, and what might cause someone to decide something radical like trying to change their gender.

Can you explain what you mean with trans ideology? because AFAIK 'ideology' means a collection of beliefs or philosophies, and I don't really understand how that applies to a physiological condition, like it does in the case of religion.