Its a bug, termination protection is suppose to overide AutoScaling and lauch configurations. Confimred by AWS support, open a ticket to get it fixed faster.

" since AutoScaling ignores that setting and will terminate your instances even if its enabled. You would have to use a launch template, and at that point I don't see much point in using beanstalk if your customizing everything." is not accurate, full of prejudice and lacks the understanding of the original question.