It is part of my job to decide on how our PP budget is allocated. Statistically, there are national gaps between 'groups' which a fair and equal society will try to close, and an inclusive education system will strive to overcome, imo.
Of course, not every child on FSM is underachieving and neglected, just like not every child from an affluent background is happier, more intelligent, more loved, more supported than a child on FSM. Those are prejudices. We are trying to focus on fairness and opportunity.
The markers are crude, but we need something to go on to make sure that we try to make education as level a playing field as possible.
For example, I start by filtering 'groups'. First check: PP, EAL, SEN, low ability and underachieving. What can we do for them? For an 11 year old with dyslexia, ADHD and dyspraxia, who is a low ability learner, who hasn't had any breakfast and who is trying to master a whole new language, a day at school is harder than for a child without these barriers to learning. So money can be allocated to one on one support, specialist materials breakfast club reading group, trips to the library or museum or whatever to engage and support this child.
Of course, we also have the child who will come up using the same filter who is EAL as they, and their parents, are entirely bilingual, their SEN is a hearing impairment which is being monitored and treated exceptionally well by parents and doctors, who are low ability or underachieving because their data is from a different education system, and whose parents are supportive and are giving their child the most amazing childhood jam packed full of educational and social experiences.
In my experience though, the filter picks up more kids near the former end of the spectrum.
You then just drop a filter every time when you allocate the money (like triage!) until you are simply offering some enriching experiences for kids whose parents would find the money to do this, but now don't gave to struggle as there is a little extra provision. For example, one of my A level students (top of the class, off to an amazing uni soon) couldn't afford the ticket to the trip to Stratford upon Avon. He'll get an A without it, but why should he miss out and the other kids who have been to the theatre often before have that educational experience over him because their parents can afford it? I just paid for his with PP funding.
It's not a stigma. It's an imperfect attempt at social balance.