I am not arguing the vaccinated are having serious cases. I am not one of "those guys" who claims the vaccine doesn't work. It's clearly still very effective at preventing serious complications and death. Later variants, we will have to see, but for now it still works very well. No debate there.
As for the spread issue, I would also agree that the vaccinated would intuitively spread the virus less than the unvaccinated.
But the narrative in May was essentially that the vaccinated could not spread the virus at all, hence they could suddenly take off their masks with zero restrictions, seemingly overnight. Now data is coming out that is changing the CDC position. The vaccinated can spread the virus. TBD on the degree to which that happens.
Vaccinated people need to chill and accept that they can catch delta, but it will most likely be very mild.
The idea that this whole deal is 99% the fault of the unvaccinated is total BS now, though. The casedemic stuff is being driven by the vaccinated now too.