Don't give up!!!! Unfortunately, many rescues and shelters have developed "rules" regarding placement, instead of looking at each individual situation. Some rescuers end up so jaded by what they have seen, nobody is good enough. Some end up control freaks, lording over their "kingdom", losing sight of the point, finding good homes for dogs. I once dealt with a rescue that chose to keep a difficult to place, adult male GSD in a crate 24/7 for 6+ months rather than allow the dog to be adopted out of state, even with vet refs, personal refs, adopter willing to pay expenses for home check and random check after placement, references from a professional trainer with a commitment to work with adoptive family/dog, to a family with GSD experience, stay at home mom, big house on fully fenced acreage. They could not find a home for this dog, who was living in crate at the vets office where he was dumped, but would not consider being flexible, even though it would have been a great placement, and there were no other placement possibilities. That being said, it must be incredibly difficult to have the responsibility for placing a dog that has already suffered due to human failure. As imperfect as rescues/shelters can be, at least they are trying. (Mostly) I know I could not do it. I foster, love every second, but could not be responsible for choosing homes. I would be one of those who finds no one good enough!!
We too went the rounds when we decided to adopt an EM. It took awhile, had some disappointing experiences with LA shelters, (a whole other story), but we finally did find the perfect girl for us at a shelter in NM.
Don't give up-there are many, many rescue groups and shelters. There are many run by caring, competent people who look at each situation. There are some who will understand and approve of your choice with Gunny, recognizing a family who bothers to learn about their pets and care for them accordingly. Don't give up on a dog that needs you and will bring you joy because of, once again, human failure.
Your new fur kid is out there somewhere, waiting for you!! Don't let someone's ignorance stop you!! Unfortunately, shelters/rescues have learned if they don't spay/neuter before a dog is adopted, it won't happen. Preventing more unwanted dogs comes before what is best for individual dogs. They judge everyone the same, and end up twisting altering dogs really young out of necessity into altering really young is best. It is not best to spay a 6-8 week old dog. Maybe better than not spaying at all and allowing pregnancy at first heat, but not best.
Don't let the fact that some people are not terribly educated and/or unable to make thoughtful decisions, resulting in the need for following an adoption checklist complete with iron clad "rules", stop you.
I wish you the best of luck in your search! Remember, sometimes you have to kiss a lot of toads before you find a prince.