It is that important. A generation of children raised on neutered and feminized language will eventually regard it as normal and inevitably arrive at the conclusions to which it leads. Maintaining classic English is not passive resistance to change, but a heroic effort of maintenance. The Jews kept Hebrew alive for thousands of years and restored it as a spoken language in Israel. Holy Mother Church preserves the Greek and Latin languages today.
Traditional language is the path to our roots.
During the long dark centuries when the world treated woman as chattel, the Magisterium in the traditional language proclaimed men and women equal in dignity. We custodians of a received mysterium fidei handed down unchanged for two thousand years depend for precision on words whose exact meaning has been honed over the passing centuries. We cannot dilute the message. It does not belong to us. It belongs to God.