This has been one of my main points since I joined here. Privatized space flights post a drastic risk to the conspiracy that is supposedly hiding the shape of the earth.
It started to look grim for the theory when the average jerk with a few hundred bucks could launch high-altitude balloons and take photographs of the earth, and the wheels come completely off when privatized space tourism became a thing.
To argue that everyone involved in space tourism and privatized space flights are 'in on it' is admitting to a scope of a conspiracy that is way too big to be believable, simply for the sheer number of people involved.
One of the points of the flat earth argument is that space flight is actually impossible- therefore, you'd be adding thousands of people to a conspiracy- Human nature would see a chink in the armor....a leak from a reputable source which would blow the lid off the whole gag.
Or at the very least, if they weren't included, these private flights would be mysteriously shut down, illegalized, or pushed to failure for one reason or another.