While it is important to be aware of textbooks, it is also good to be familiar with other materials used. There are many teachers who do not use textbooks in classes, but the other materials are just as bad and are geared to the UN agenda as well.
Along with speaking out against such biased and ridiculous textbooks, those interested might also consider checking with classroom teachers and working to influence central committees who make the final decision on textbook selections for the districts and even for each school. The scarry thing is that it might be possible to stop bad textbooks from being adopted and still end up with UN agenda thru other materials used in the classroom. Safest bet is to homeschool, and if that can't be done, then read your child's books with them and counter the nonsense as you come across it.