Got my response from Strava:
Hello,
Thank you for sending us your feedback about this segment. This system is in place to keep the competition safe on Strava, and it relies on the feedback of our users. Because we are not in a position to evaluate the hazards present on a given segment, we have to take the comments associated with segments flagged as hazardous very seriously.
We understand that the current functionality of this feature is limiting, as after one person flags a segment as Hazardous, the entire leaderboard is removed for all users. This can be frustrating because what one user thinks is a hazardous segment might not be judged the same way by another user. We are working on ways to increase this functionality in the future, but for now we are unfortunately unable to remove the flag from this particular segment, as the comments do indicate a legitimate potential hazard:
"Segment contains multiple stop signs many riders are ignoring."
Thanks for your patience while we work on improving this experience.
Best,
*****
Strava Support Team
"Segment contains multiple stop signs many riders are ignoring."

?!?
So I've made another identical segment. Let's see how it works...