So... I don't think that study says what you think it does.
First group (Delta Cases): look at how low the "total cases, > 50" number is versus the "total cases, < 50" number. Only 9,571 cases in 4 months for the far more naturally vulnerable, yet heavily vaccinated, population versus 82,458 for the < 50 population, which has stronger natural resistance, yet a much lower vaccination rate. The vaccine is clearly providing some protection against symptomatic cases.
In the ER visits sections, the "unvaccinated" numbers are 6-8x as high as the vaccinated numbers. 190 (vaccinated) versus 1,571 (unvaccinated) for ER visits. 80 (vaccinated) versus 484 (unvaccinated) for overnight admissions.
I'll give you the deaths (50 versus 44), but that's a fairly small population overall and 88 of the 94 were over 50 (likely had complicating health problems), and all 6 of the under 50 deaths were unvaccinated.
One major complication with interpreting these numbers: they were collected during a phased vaccine rollout, so the vaccine percentages changed significantly over time. So, early on, basically nobody under 50 was vaccinated, so the nearly all cases went in the unvaccinated column. The opposite is true with the > 50 crowd: by June, vaccination rates were so high that the vaccinated population dwarfed the unvaccinated population.
Still, the fact that total case numbers and hospitalizations were so low in the < 50 group shows that the vaccines work. Everybody knows that covid is far more dangerous to the old, and yet here's data showing more ER visits by the young and roughly equal overnight admissions.
