I grew up in a deprived area - I am not defending the words used at all, but she would have been known to not be 100% white, and, during the late 70s and 80s, this would also have led to abuse - from memory, 'mongrel' and 'half-ch*t' were common phrases (directed at my nephew/his mum). I'm talking of a time when national front graffiti covered all surfaces that weren't flypostered, broken glass everywhere, yes, white dog shit on the pavements and everybody hid on Saturdays when Millwall were playing the local team.
The way some kids deflected attention away from this/tried to fit in was to be overtly racist towards others that were more visible.
It was also normalised to use 'Pa' as a descriptive term, rather than solely as an insult - we grew up not knowing 'Mr Patel owns the Pa Shop' was abusive, as it was a million miles away in intent from 'Oi! YOU! PA LOVER!!!' being screamed out of a van at you for walking home with your mates as you got older. It was actually the latter that led to me realising it was offensive, as it was screamed in the same way that N* LOVER!!! was hurled at us.
I'm not proud of being brought up so ignorant that I had to ask my best mate aged 13 what word I should use instead, because I knew the proper words to describe somebody who was black/Jamaican/African, but I didn't have a clue what I should use for her. She answered without showing hurt or offence that 'if you know for sure where someone comes from, say Pakistani, if you don't, Indian'.
Had there been a kid at my secondary school with the surname Shetty, though, there's no doubt that they would have been called Shitty instead of anything directly racist. Anybody who had the name Tucker would have been called Fucker - and we all know Jeremy Hunt's misspoken surname.
She grew up not just ignorant, but with somebody who quite clearly was racist and, bring an addict, would have been even more likely to be verbally abusive as a means of attack being the best defence. How could she not have learned from that? It was noticeable at the time that the one from S Club 7 came across as far more intelligent and manipulative, too - the type of person who, as a kid, would wind up the less bright and watch the result.
It's not an excuse, but the comparison might be useful, as whilst it is blatantly obvious now those things should never be said, if you were dragged up in poverty in horrible circumstances in the 70s/80s, you learned horrible things without knowing they were horrible unless somebody walloped the speaker or you heard it in a threatening context - it was only in the 90s that (shit) schools became proactive in teaching inclusion and stamping out racism.
It was easier to pick on the less educated, easily manipulated woman with a background of casual racism and verbal/physical abuse (who incidentally happened to have a sex offender with a fondness for less intelligent girls as an agent) than look at all of their behaviour.