I've seen this kind of thing a lot on HBT, and frankly it surprises me. Some people will say they don't pay attention to water and their beers are fine, but don't realize they got lucky.
That's why I bolded and emphasized the "IF" above. You have to make assumptions for the "water doesn't matter much" argument to hold.
You might be lucky with your water, but it's only that. Luck. To anyone who says water isn't important, I say to them: Try brewing with my tap water and then see what happens.
On the other end of the scale, there is the gut reaction that any problem gets attributed to water. I have used tap water in RI, the one I said was considered the best tasting in the area. I have used distilled with adjustments. That did not make a significant difference. I have used FL water. It doesn't seem to give me consistently as good results as the RI water. But the beers are very good. I will at some point get an analysis and make some adjustments.
Maybe your tap water is an UNLUCKY thing. Maybe the majority of municipal water is OK?? I don't know.
But the knee jerk reaction to a problem.. What is your water??? It may or may not be relevant....
IMO the idea that to make good beer you have to adjust water chemistry is overblown.