It always used to bother me that Elly resented the idea of having pets in the house. She was obviously incapable of understanding how they behaved which made her a lousy pet owner. This told me that she never had a pet growing up; simply put, she doesn't understand how animals behave and never will because her parents prevented her from being exposed to them. I also remember seeing that Dixie first appeared, Jim told the others that Marian wouldn't have a dog in the house no matter how much he and Phil begged. This makes sense because there are a lot of women who keep their homes pet-free because of fears of dirt and disease. Since my gut tells me that Elly was as big a suck-up growing up as Liz was, she never really questioned that. She might rebel against Jim's plan to keep her from marrying Mister Right by being made to stick a B.A. to her name instead of dropping out and getting her MRS but she never questioned the assumption that dogs were filthy and disgusting. Once she started to realize that Farley was never in any real danger of being put down, she started to resent him because John and Mrs Baird had made her bring a source of contamination into the home. Just because his mother tolerated does meant nothing to her. Only her mother's way of doing things is valid.