Granted, Brian has dated humans on Family Guy before without the taboo of bestiality being broached, but the story line didn’t seem in line with the original statements from the Family Guy team.
As an example, a recent storyline featured Brian dating Joe’s father, who is transsexual.
Perhaps some clarity will surface on the show’s stance after this recent episode.
Brian was ashamed of the fact he was dating a transsexual woman, though there was no reciprocal shame on the part of Ida for dating a talking dog.