The engineers are influenced by who pays them, they also have biases. I believe they believe what they say about the subject. I just don't care because they never provide proof to show me how the DS is unsafe.
I ran over a full size pallet that blew off a truck on the interstate at 75mph. 5k+in damages. The front MC tire went flat, the rear car tire did not. Both rims had a 5-7 inch flat spot in them. Progressive did not care about the tire. They didn't even care what I put back on it. The dealer however would only replace it with a OEM tire. After all was done I questioned the adjuster about the car tire, he stated as long as it was a DOT approved tire he could not refuse to cover the damage. He also remarked that he sees a lot of bikes with car tires and to his knowledge it has never been questioned by Progressive.
To each his own on the safety question but I would really like to find an example of a insurance company who has refused to pay bc of a car tire. If they did that to me they would be talking with my lawyer.