So those jpegs have been processed from the camera's raw data.
Every photographer with a digital camera shoots raw, whether they realise it or not, and the only difference is whether the photographer gets the camera to do the post processing internally to output an image (sooc jpeg) or whether the photographer does the post processing using a raw converter app to output an image.
So who knows what post processing settings were set in the camera when those photos were taken. There could have been heavy noise reduction, sharpening, colour profiling, contrast, brightness etc etc etc processing applied to the raw data to output the jpeg images which were then stacked.
Therefore, Ian's critique is totally valid. Whether you accept it or not is your choice to make 🙂
Hopefully one day you will understand the potential benefits of maximising the quality of the raw data allowing images of higher quality to be created compared to sooc jpegs.