It's not quite as bullshit as you make it sound. The idea is that when something is communicating wirelessly at all, it's doing it through the matrix, which is why there's no "wireless direct connection/handshake range" like there was in 4th-- Not that 4th edition is relevant, since it is stated in-universe that they practically rebuilt the matrix (again), which isn't an uncommon occurrence.
As for the "wireless is faster than wired" I was of the understanding it was because wireless devices essentially join the matrix cloud and have accessed to unused processing power in other devices. It makes enough sense to me.
And one major thing... It's not "because science". It's "because science fiction". I dunno if you noticed, but the real world doesn't have full sim-sense VR, global wireless internet, the ability to mentally link with machines to control them as natural extensions of your body with no training (and in fact in such a way that makes it easier, because of how control rigs work). It's one thing to say "we have guns, and guns don't fire like that" for things like balance issues, but the real world has very little that is commercially available that you can compare to how the science fiction part of Shadowrun works. And really, trying to is like saying you think mages are dumb because magic doesn't exist.
The problem with this line of thinking is that it is non-sensical. Think about it for a moment. Who built the new matrix? Megacorps had to have had a hand in it. There is no way the megacorps would design a system that forces all of their data transfers to be even more prone to hacking.
As for processing power. Again, we run into an issue where apparently most devices have had their processing abilities drop in the past four years. This is the opposite of how it should be. Technology improves. We get faster processors every year, not slower. Additionally, designing your software to have to make use of random other processors to work is sloppy design. No decent tech firm would do that.
Your last paragraph is flawed. It's not just science fiction, it's science fiction with twenty years of past history that we can look at and compare. Sure, we don't have real life DNI, VR, etc. We do have what we know about 2070, 2065, 2060, 2055, and 2050 DNI, VR, etc. to play with though. Comparing SR 5 DNI benefits to SR 4 benefits shows that DNI has been mutilated for no reason at all.
The only plausible reasoning for this is that, from a design point, they wanted hackers to have an easier time getting into things. They then built a hasty and flawed justification for it.
I liked the though of wireless bonuses when I first heard them, I just think most of their execution was flawed. Most of these bonuses should be possible without connecting to the internet.
Think about some of these wireless bonuses for a moment. I list two major offenders to common sense.
Silencers for example. Let me get this straight, my accessory that is either A.) Illegal or B.) part of a black op needs to be on a ridiculously low security wifi connection for full functionality? Seriously, who would design it to work this way? No one. No logical person would ever design this device to work in this manner. I makes no sense.
Now, let's look at Airburst Link. These exist today. They program the grenade just before it fires with the distance it explodes at. Why does the tech sixty years in the future have to rely on a less secure system? Again, it makes no logical sense.
As a programmer, there is just no way any group would rebuild a less secure system unless the intent was to make hacking easier and harder to manage.