The real reason is that they see false gods as no threat to their monopoly on power. They only see true gods as a threat. Ergo, they only attack Christianity.
Good parents should be less worried than this writer seems, at least for their own children. And kids whose parents are uninvolved? They're in trouble unless they meet a positive role model. That's why we have Scouting and other community activities for kids.
There are centuries of informal research on what works - passed on as the traditions of Western culture that have survived because they work. I believe in exposing kids to even the unpleasant aspects of life, but in a controlled manner. Children can handle far more than we give them credit for. If the collectivists want to expose our kids to sexuality in elementary school, we can deal with even that whether or not we home-school.
I have no problem with reading relevant Bible verses to my kids, discussing the scriptures in detail, coordinating my lessons with in-school indoctrination and explaining that some people have desires that are not good for them. Just as my young kids (years ago) would overeat after Halloween, and they need adults to guide them away from those unhealthy urges, other people have unhealthy sexual desires. The fact that they want to do something is not proof that following those urges is good for them.
I have (on many topics) explained to my children that God has given us guidance in the Bible for our own good, because following our superficial urges would harm us. If I had to deal with anti-Christian indoctrination in school, I would add that even people who are otherwise trustworthy and good can be wrong on one or more issues, which is why they should reach their own decisions - but those decision must be based on the superior guidance of their prayers, church traditions, reason, and scripture.
However Jesus said you would be persecuted, so you call it persecution when other people objection to being pushed around.
Still praying? Matthew 6:6