No child can get baptized without the approval of their parents. This has been the case in the Mormon church for some time, at least since the mid 80's when I was a missionary in Central America. By the same token, nor can a married adult be baptized without the consent of their spouse. A child from a polygamous family cannot either.
There are groups of people and areas of population where the LDS church treads very carefully so as not to put the safety of the native people in jeopardy. Take, for example, the proselyting in communist countries, or of Muslims. There are cultural differences that make it deadly for those in some cultures to convert to Mormonism/Christianity. Policy's that have been in place for some time are an issue of safety.
The only way same sex married couples would be able to live as their son or daughter believes as new members their parents should live would be for the couple to split up, and that is not what the LDS church wants. No prophet of god would ask that any child, or anyone in a culture that would harm them, to have to choose between their family and their religious beliefs -- though some have made that choice.
Regarding the referring to same-sex married couples as apostates. Apostate is a strong word that we associate with anti-Mormons who cause pain to members of the church both in modern and ancient times. The current, accepted definition is thus: A person who renounces a religious or political belief or principle.
Second is the issue of judging and being judged. Judgment is not mine. Judgment is not yours. Judgment is His. And sometimes he delegates judgment to his servants. No one else.
A point I would like to make: People are being treated individually. This is not a blanket that covers anyone to shield them from the light. Bishops and stake presidents/mission presidents have been instructed to handle any exception themselves. Personally. This requires meeting with those involved who wish to be represented.
Are there extras that have to happen for any child who is in a home where the heads of that home are considered to have apostatized from the church? Yes. There may be extra steps they would need to take for other reasons as well. I myself had extras I had to do in order to marry my wife because I am a gay man.
We are treated like individuals.
I must tell you that I am feeling much better about the recent events after I studied a bit and kept an attitude of prayer. While I grieve for those who are hurt by this action, I rejoice in the fact that God is just, and that His judgment will be fair and will be made out of love for us – with our best interest in a mind that is infinitely more complex than ours.