Missing explanation why code raises 'Writing to hive not supported'

There is code in pyhive/sqlachemy class which suppose to prevent writing to hive. But there is no other explanation in docs, git log or whatsoever why writing is not supported.
The writing is works for raw queries. It also works if this part is commented out
Same for sqlalchemy_hive.HiveStringTypeBase which omits implementation of python_type

see https://github.com/dropbox/PyHive/blob/b21c507a24ed2f2b0cf15b0b6abb1c43f31d3ee0/pyhive/sqlalchemy_hive.py#L37