I dont see this as solved but I also came here with the same problem, though my solution is going to be to install python3 on the rhel6s and add a variable to my inventories for the RHEL6 and some RHEL7s we have bound to 2.6.
Var should be
ansible_python_interpreter: /user/bin/python3
or where ever python installed at, as long as you dont change the servers configs to source python3 all will work still.