Django LTS won't fix one line for Python 3.7 compatibility

I agree with them. They have a policy and they chose to respect it. Otherwise it will be: fix these 2 lines, fix this small class etc.

Instead of throwing work onto the django team and suggest to break the policies, why won't you do the work and upgrade to 2.0?

There are no small changes. You have to test, change tests, write tests, do new releases etc.