In 1930s mysteries, all sorts of motives were credible which aren't credible today, especially motives of preventing guilty sexual secrets from coming out. Nowadays, people sell their guilty sexual secrets.
Every diminution of the public burdens arising from taxation gives to individual enterprise increased power and furnishes to all the members of our happy confederacy new motives for patriotic affection and support.
The motives of these parents vary, many parents don't like the curriculum being taught to their kids, or are wary of the threat of peer pressure or the presence of drugs or violence lurking in too many of our schools today.
When any government, or any church for that matter, undertakes to say to its subjects, This you may not read, this you must not see, this you are forbidden to know, the end result is tyranny and oppression no matter how holy the motives.
This kind of charge reveals a good deal about the personality of the people who make it; to impute such motives to another man is to imply you're harboring them yourself.
Sometimes, his methods and his motives are questionable and even his morals are questionable in the way he does things. But I think his intention is always to protect his daughter.