Affiliation they mean with an institute/company funding their research/work. It's quite rare, if it ever happens, for someone to find an innovative algorithm, let alone write a technical paper, as hobbyist.

What a strange expectation. Obviously humans didn't wait these institutions to create ideas and notations. The fact that these institutions now exist don't make individual with own desire to express novel idea disappear. All the more when these institutions with their elitist mindset will actively reject whatever is going too much of the rails of their own social bubbles.