The thing is the viewpoint of opening without mitigations is as extreme as you believe a viewpoint of complete closure until vaccine to be.
There are compromises that can be made but they take work, effort and, in some cases, funding. They are not impossible just politically inconvenient for a current Government.
I've said this before and will probably say it again but these things should be at least considered:
School-based measures could be secure funding for enhanced cleaning, the use of visors or windowed face coverings or screens to help reduce transmission, the tightening of restrictions on the attendance of unwell children, etc.
Community-based measures could be things like better distancing for families and their children, possible restrictions on how open our society is (as stated by the scientific advisors) and making it easier for parents to take leave to care for an unwell child or one who is having to isolate due to a positive result from someone else in the classroom (this would include Government support for the businesses that this affected).
And to improve remote learning if/when it's needed there needs to be support and funding put in place to ensure that all students can access online learning platforms. This includes investment in technology (that was said was coming but didn't) and in training for staff and online tutorials for parents to help them access a digital platform such as Google Classroom.