As another PP said, there are always some parents who see school as childcare, somewhere their kids go so they can work or do what ever else they need to do without their kids with them. They won't see school as a benefit for their child, giving them opportunities for the future and their ability to support themselves financially as adults. This may be because they didn't have successful or beneficial experiences in school themselves.
Some parents though will also think it doesn't matter, because the odd day here and there won't have an impact (parents, it can absolutely have an impact!). Some parents will feel that as teachers are striking then they can feel justified in taking the odd day here and there.
Parents (and I'm one too, as well as a teacher) - education is there for your child, not you. To help them reach their potential, so they can have a choice of careers in the future, whatever that choice is.
[Also the soft skills like being part of a group, teamwork, negotiating tricky friendships, resilience etc]