I don't think anyone blames the little guy who sells out for a fortune - good for them.
What I have issue with is that AB is buying up all these small craft breweries, and then providing very lucrative incentives to the distributors to sell 98% of their product. That only leaves 2% shelf space for the small guys if they are successful.
Say 'craft' beer has 17% of the market (I don't know what it actually is), if only 2% is available for the independents, then AB will be providing the other 15% of the craft beer, (or ~95% of the craft beer market).
Once they have established brands, and a lock on the market, what would a big shareholder owned conglomerate do to increase profits? If I were them I would look at every possible means of reducing costs and increasing profits. This will mean ingredients will change, processes will change, and most probably the resulting beer will change. I'm sure they will keep small batch 'Flagship' beers unchanged, but you will also pay for them, the rest will be 'diluted'.
AB's primary business is to make money, and as much as it can from it's resources. Always looking to increase ROI. If it doesn't, then it's share value will fall. It just happens that the way it makes it's money is thru making and selling beer.
I suspect how good the beer tastes is NOT a metric within the company. Sure good product helps to retain customers and sales, but it is the sales that count, not how good the product is.