Not an impenetrable shield is an important point. In many areas, it was an even more important 5 months ago when spread was much higher.We know vaccinated people are continuing to contract the virus (it's not an impenetrable shield), and the virus is replicating well enough for people to test positive.
Combine that with this map.
Someone in a blue low transmission are, the vaccine is probably all the mitigation needed. Someone unvaccinated, good ventilation is probably enough too.
Someone in a high area though, it's more questionable. Some extra mitigation beyond the vaccine is probably a good idea when in poorly ventilated areas with unknown people.
If it's raining, and the vaccine is a rain coat. In a light rain, it's more than enough. In a stronger downpour, having an umbrella too would be nice. If it's a hurricane, both may still not be enough to keep you completely dry.
From that map, I don't think there's a hurricane level of transmission anywhere in the US. Perhaps MO is trending towards that.