Jon's burns were a result of steam burns from sweat under his leathers--this was posted by him in another similar thread last year.So it had nothing to do with perforations or fuel getting throught the perforations.The burns would have likely happened with any leathers.We get similar burns when we get too much heat and the sweat under our turnout turns to steam.
Besides,fuel next to your skin is not going to burn,remember it's the vapors that burn and not gonna be any with the proper mix of air between your leathers and skin.
Nomex and similar modern fabrics are your friends when it comes to fire and should be encouraged,not prohibited.What do you think firemen wear--Nomex turnouts,nomex hoods,etc.
Leather is NOT fire resistant or retardent.