I’m no expert but I believe incorrect oils can cause seals and gaskets to swell up and deform and not correctly and in some cases the components can start to break down.
Whilst I’m sure that’s possible, pretty much all brakes are milled aluminium and I would guess the seals aren’t that different, they probably all come from generic 3rd party suppliers eg I doubt Hope make their own seals (otherwise they’d be milled out of Al).
Mineral oil will cause natural rubber and EPDM rubber to swell . Natural rubber is porous and absorbs oil. EPDM is not oil resistant.
I didn’t think anyone used natural rubber for anything anymore as there are cheaper synthetics available.
DOT brake fluids are compatible with both natural rubber and EPDM.
Shame they’re such horrible stuff to work with – although if you ever want to annoy a car owner, splashing a litre on their car will strip most of the paint off it…..