Welcome to the foums @Cameron_Gross
You could vote up this …
Same applies to all integrations, not just Strava.
In the meantime, you could try contacting the author of activityfix.com and see if he could add changing of privacy settings to his rules based app. I currently use the app to change the bike type recorded in Strava from my default bike, to something else based on ride type (“virtual ride” I think is what Zwift send to Strava), so adding an option to change activity privacy to private/followers etc should be possible, if Strava let him access that in the API.