I agree - if someone my age hit me, I would probably hit them back, or shove them or whatever. But if it was an obviously frail elderly lady, I really don't think I would. I'd move away so she couldn't hit me again but pushing her, that would just feel wrong. I don't think the Defendant comes out of this at all well, and she really should have been given a custodial sentence.
I think the staff should also be ashamed of their part in it all, had they dealt with it differently the whole incident could potentially have been avoided.