For many religious people, raising their children in their faith is an important part of their religious practice. They might see getting their kids into heaven as one of the most important things they can do as parent. And certainly, adults should have the right to practice their religion freely, but children are impressionable and unlikely to realize that they are being indoctrinated into one religion out of the thousands that humans practice.
And many faith traditions have beliefs that are at odds with science or support bigoted worldviews. For example, a queer person being raised in the Catholic Church would be taught that they are inherently disordered and would likely be discouraged from being involved in LGBTQ support groups.
Where do you think the line is between practicing your own religion faithfully and unethically forcing your beliefs on someone else?
I think it can be done if the parents are tolerant, flexible, and understand that people are naturally curious about other worldviews. Unfortunately, that’s a stratospherically high bar for a lot of people. When the parents sincerely believe that their child’s eternal soul is in danger, ethics come second.
Ironically, I think the people best suited to give religious guidance are agnostics, who readily admit that they don’t know squat about the afterlife or other supernatural topics. Ideally, they won’t pass on hate or bigotry whose only basis is ancient hearsay or hallucinations.