"More of them" means nothing when looking at what a photosite captures on a sensor in regards to exposure. So exactly where is the source for all this internet nonsense?
A photosite doesn't magically record more photons just because it has more siblings around it. A 4.7micon photosite, whether participating on a larger FF sensor or on a smaller APS-C, should capture the same amount of signal, within an error tolerance. The light doesn't hit it differently or for a different amount of time, it would hit both equally if using the same lens and same aperture/shutter speed, correct?
If you disagree, then present good argumentative material, instead of attacks, jabs and the general internet bully-ing. Maybe he removes your comments due to tone and attitude?
Another fairly easy article to read: http://reedhoffmann.com ...r-especially-with-pixels/, but perhaps he is a troll too?
And another... https://www.lensrentals.com ...nsor-size-matters-part-2/
Overall sensor area doesn't contribute to the pixel-level ISO performance as the size of each photosite itself would. The reason this was touted back 10 years ago was that we had at no point a FF sensor with the same photosite sizes as an APS-C, so it was easier to say "a big sensor is better than a little sensor" then to get into technical discussions on photosite sizes. These days, we now have FF and APS-C sharing almost the same sized photosites, so the decade-old "lazy answer" simply doesn't hold true any longer.
When comparing a FF to an APS-C, and one knows the resolution of both, then the FF should perform ISO-wise better at the pixel level if a) the technology of the 2 sensors is of the same generation and capability and b) if FFres / (1.6 x 1.6) < APSCres.
(I think I have that equation right anyways)
Nobody is arguing about the exposure. That youtube troll can't tell the difference between "exposure", "light intensity", the "amount of light" and "image brightness", it's all the same to him. And you too, apparently . OK, a short lesson:
intensity = aperture
exposure = intensity * time
amount of light = exposure * area = intensity * time * area
image brightness = exposure * sensitivity (ISO) = intensity * time * sensitivity (ISO)
Now the important part, different sensors have different sensitivities at the same ISO numbers, because let's say 4µm dot cannot produce the same SNR as 6µm dot. When the dot size is the same, larger area provides much more dots and therefore much more data than the smaller area and the data is all that matters, even if the amount of noise is increasing along with the area. Information = Quality. More information - better quality.
Tony Northrup understands it much better, so you should watch his videos instead.