Surrey County Council paid for all existing pupils at RGS to continue their studies up to O-level,which included Starmer.
Over the following 2 years - whilst he was able to stay, with his fees paid by SCC - RGS became successful with hundreds of fee paying students joining. That allowed the headmaster, Howard Ballance, to set up bursaries that would allow "gifted but under-privileged" children to attend for free. Starmer got one of those, which allowed him (unlike most of his grammar peers) to finish his A levels at RGS.
He got his opportunities paid for by the paying RGS parents at the time.
So yes, he's showing a complete lack of appreciation and gratitude for what he was given by private school parents exactly like the ones he's started a class war against.
Fuck him.