I haven't heard this. What's so bad about it? I don't eat in there that much. I generally eat a hot dog or two at The Dugout so if the food is worse than that then I will say a prayer for you all.
Mark laid it out nicely, but I can elaborate. The food is basically the level of really bad fast food, and there aren't really any options beyond that. Example: my son orders a hamburger. It comes as a tiny, charred disk on a stale bun. Everything about it is dry as if it had sat in the desert sun for a week. It cost $9. My son will eat hamburgers for breakfast, lunch and dinner, and he ate about one-third and put it away. That's one example of many to provide context. Note that there aren't any real options besides stuff like that except for a couple of places that are a small increment better, are difficult to find and have long lines.
I get that I am going to overpay for food in a captive environment - that's just how it works. But, for god's sake at least give me something that is good quality. Yankee Stadium food is not even the quality of McDonald's. Meanwhile, you can go to CitiField and eat at Shake Shack. I've been to other stadiums, and Yankee Stadium is hands down the worst, and it really should be the best.