I personally have not seen many good working dogs struggling to find homes because they were desexed, although I don't do Schutzhund. I've personally seen several desexed Schutzhund/protection-trained dogs placed in new homes in the last couple of years too, even though I'm only peripherally involved with those circles. It seems to me that a good working dog generally has value beyond their ability to breed. Now, sport dogs are a bit different, and IME again it is hard to make a universal statement about whether reproductive ability matters in their ability to find a new home--it seems to be hard to find a home for them regardless.
Personally, I don't think that people should be criticized for making a responsible choice about whether or not to spay/neuter, regardless of whether one personally agrees. Keeping an intact dog can be a lot more work than some people--even working homes--are comfortable with, and I've even seen provisions in homeowners' insurance and rental agreements banning intact pets. I'm beginning to look for a new dog myself, and reading my homeowners' policy, there is such a provision--we'll have to either see if we can get it removed or switch carriers if I choose to get a dog I want to keep intact, which may not be feasible for everyone.
The only time I'll complain about someone's choice regarding spay/neuter is if they choose to leave their dog intact, and then can't handle it responsibly--either by being unable to handle natural behavioral issues that may crop up, or by letting it have access to other intact dogs and having repeated "accidental" litters. Otherwise, I can't really get too worked up about it. JMO, of course.
The rowdy dogs:
Hector-2 y/o GSD (mix?) rescue
Scooter-12 y/o ACD/Border Collie mix
Bandit-8 y/o ACD
Wooby-14 y/o ACD
Abutiu "Abi"-ACD puppy and hopeful future SAR dog!