Here’s a neat tid-bit. A group tried to use “a person’s a person no matter how small” from Horton Hears a Who! as a anti-abortion slogan. According to the Morgan & Morgan biography Seuss would not allow it and said he would take legal action, so they stopped using it.
Also, while How the Grinch Stole Christmas is a celebration of the holiday Christmas, Dr. Seuss very intentionally made it secular and did not including any specific religion in his books. Instead the book is a reminder that Christmas should be about friendship and love instead of commercialism and presents.