It's all in how much of a size, weight, and bulk/volume difference a person is looking for, and what each person considers 'significant'. Look at automobiles - most people agree that a Honda Civic is smaller than a Honda Accord - even though the difference side-by-side doesn't look astounding or drastic - sort of like an A7 next to a Canon DSLR. Sure, the Honda Fit is smaller still, and on the larger side, a large SUV like a Suburban is massively bigger. But one need not move from a Suburban to a Fit to feel like they're driving something smaller...there are many steps in between.
When I look at your comparison photos, I still see what I would consider a pretty big difference in overall volume and bulk. Rather than just looking at the top view, look at the front view to see how much shorter the A7 is - and the side view to see how much thinner it is. To my eye, that saves a lot of bulkiness and volume, and makes the camera FEEL much lighter and smaller in the hand. It's the same effect I get with my A6000 compared to an APS-C DSLR - the overall volume, ie: the 'bulk', is so much less for me that the camera just feels lighter, smaller, more maneuverable, and easier to carry. When I'm hiking through the swamps in the summer at 100 degrees, I can guarantee I feel a major difference walking 10 miles with my A6000 compared to my A580...even walking around Disney with a 10mm ultrawide zoom - the A6000 and 10-18 feels significantly lighter and less bulky than my DSLR with 10-24.
I don't think people who point out the weight, size, or bulk advantages of mirrorless are exaggerating or misstating anything - they just find the difference to be more significant to them than you do for yourself. And they're not claiming that no matter what lens is attached, the mirrorless is hugely smaller or lighter than a similar sensored DSLR - sure, stick a 150-600mm lens on both, and the body size difference becomes almost irrelevant - but there are smaller, lighter lens options you can use and make the mirrorless a good bit less bulky and lighter than a DSLR with the same lens, and there are several lenses you could bring along that would fill roughly the same space in a camera bag that the DSLR would with just 1 lens. I have a bag that can fit my DSLR with a 30mm F1.4 lens attached, and nothing else. That very same bag can accommodate my A6000 with 30mm F1.8 attached, PLUS my 10-18mm UWA, PLUS my 55-210mm lens, PLUS my 18-55mm kit lens. Same bag, same space - but fits camera plus 4 lenses instead of camera plus 1 lens. That's where the body volume makes up a very big difference with the mirrorless kit - and my mirrorless is far from the smallest model out there.