Well, you also underestimate many kennels. Do you think that none of these places that deal in dogs as a profession can handle a difficult dog?
My last Malinois was not easily handled by strangers. We would board him at a place where he had a covered indoor/outdoor run that he was never taken out of. His kennel was cleaned by tossing treats in one end or the other, then blocking him in or out so that he wouldn't come into contact with the kennel workers. Only the owner of the kennel was allowed to handle him. He didn't like her, but she was experienced enough that she could get him out and deal with him if needed.
Quality kennels exist, you just have to find them.
My last Malinois was not easily handled by strangers. We would board him at a place where he had a covered indoor/outdoor run that he was never taken out of. His kennel was cleaned by tossing treats in one end or the other, then blocking him in or out so that he wouldn't come into contact with the kennel workers. Only the owner of the kennel was allowed to handle him. He didn't like her, but she was experienced enough that she could get him out and deal with him if needed.
Quality kennels exist, you just have to find them.