The first real caring interaction they experience is at the rescue centre in the UK, that's if the dogs are comfortable with touch; yet many dogs leave the centre too frightened of people to even allow the staff to touch them so the first nice hand that touches them will be in their forever home.
All the kill-shelter workers tend to be men, and most are employed via the government - they have not chosen to work with the dogs because they like dogs, they have to work there to put food on the table. You will find a clear difference in the attitude of people that choose to work with animals because they like animals, to those that have no other option and unfortunately this is also display via their treatment towards animals.
Rommies tend to be much more suspicious and fearful of males in the home due to their past experiences with men. It has nothing to do with your partner/brother/son/housemate personally, but the dog is fearful as they associate men with pain and abuse so we need to help them understand that not all men are scary. If your rommie is the other way around and is fearful of females, it is much more rare but it can happen - following the guidance below can help to create a bond with you family member/friend and dog.