Karen was definitely not being condescending. She is 100% correct in gliders cannot be used at stud like you do with other animals like cats and dogs. Gliders bond
very deeply with their mates and the male is an essential part of helping with the joeys. Without daddy there to help mom can get very stressed and may even pull the joey(s) before they're born. There's also no guarantee you'll have more than one joey.
I know it's not what you want to hear but if you want to breed your girl you would have to add the male to your current gliders. And, one last thing to think of is just because the gliders are paired together and are a good fit lineage wise, it doesn't mean they'll ever have joeys. Some gliders just don't want to be parents no matter what we do