When somebody attacks you on some of the features that define you (your work, your values, your reputation), all you can do is continue nurturing those very same features.
Going head-to-head can be fascinating in a sense. Demolishing the attacker’s argument, pointing out all the good that you have done, bringing people onboard to testify on that goodness, providing evidence that what you say is correct. Fascinating, and costly. And eventually it will most likely play in the hands of your opposer.
You are in it for the long term, not for the next news cycle. Work, values, reputation are built over time. Let others craft and enjoy the hourly commentary, the back-and-forth, the speculation, as it will be soon gone.
You, on the other hand, are here to stay.