Respectfully, its not that simple. I dont think you know what you are talking about.

I think it's better to steelman rather than assert ignorance on the part of the person you're replying to.

It is true that people these days associate the DSLR form-factor with professional photography, despite the heavy use of rangefingers by those such as Robert Capa etc not that long ago. And it is also true that both rangefinders and mirrorless ILCs avoid the need for retrofocus designs which in theory should make for higher-quality lenses at the same weight, or similar quality and a lower weight.

As for "better" this is often a matter of preference and it's okay for people to have different preferences. For me personally, I wish there was more experimentation in ILC form factor, it seems most (with a few notable exceptions) ape the pentaprism hump even if they don't contain one.

I think it's easy to see what they mean, even if you don't agree with them. I think it puts too much emphasis on glass as there's so much more that goes into getting a shot. I do pick up my old film cameras every now and then for enjoyment, but if I have to get a shot, I'm always taking the newest thing I have. It's hard to beat multiple stops of stabilization in the lens and the body along with the black magic of modern sensors.