I know people in the US who are not jw's and take their homeschooling very serious. They opted out of the classrooms when things like drag queens were being welcomed for reading hour with 5-7 year olds, when gender books were supposed to be normal and so forth. Some parents just don't agree with some of that and that is their choice.
That being said there is testing for these kids but that is state by state. Some states are more rigorous than others. In years past I would agree that many home school kids were just plain weird. sorry to say so but that is my opinion. Now there are so many options and programs for home school kids that is not necessarily the case. All depends on the parent I guess.