Most soaps try to explore real-life situations with a degree of even-handedness and realism - let's face it, this is the only place some viewers get to know about such issues!
I don't watch any soaps, but I would suggest that Sally's reaction is pretty typical of a lot of mums who simply don't know how to deal with their daughter's burgeoning womanhood, coupled with the fact that she is wearing comfortable shoes.
From my experience, the writers will develop this thread and hopefully Sally will become a little more educated and tolerant and realise that love is what matters, not gender.