"No-one came back with any other issue.
Those ARE the issues that determine infection rate in sexual transmission."

OK, one last attempt to elicit understanding.

Take two groups with infections, in the period between first infection and the index diagnosis

In group 1, two percent acquire the infection.

In group 2, 33 percent acquire the infection.

The infection is one that doesn't go away, being manageable, but not curable.

A single sexual encounter with anybody in group 1 carries a one in fifty chance of infection.

A single encounter with a group 2 partner carries a one in three chance of infection.

Once the cause is discovered and research into treatment begins, the infection rate drops, but like drink/drive cases, after a time starts to rise again.

Since the infection is still there in the same proportions, which group is going to show the higher rate?

And that will happen with or without promiscuity being involved, because we are talking about proportional risk, and the MSM proportion is the same as it was because the virus doesn't go away.

In other parts of the world the proportions are very different and the infection rates reflect that.