Why? Because loud shows at meals at both Disney Parks and
DCL are the exception, not the norm. But on the Wish, 2 out of 3 restaurants not only feature entertainment, but loud in-your-face type of shows instead of something in the background that adds to the ambiance or comes in short bursts. It's just personal preference, but it isn't an overly picky one in my opinion. I think it is likely there are many people like me who love what DCL has to offer, but also like a dinner where they can talk to other humans. There is plenty of flashy entertainment outside of dinner.
The Fantasy, which we love, only has a dinner show in one of three restaurants, and it is much less in-your-face than the two on the Wish. On the Magic, we didn't care for the Rapunzel show, as it made it difficult to talk, even with our servers, which is a pretty important part of dining. (It was also a rehash of songs you see in the full performance on the ship, which seemed rather redundant).
As for the parks, where are you seeing these types of shows? Because all the highly-themed restaurants I can think of have nothing like these shows.
The shows probably won't keep us from trying the Wish if it ever switches to a 7-day cruise, but it will be one factor that we would consider. I mostly like the look and feel of the ship, but find this particular aspect unappealing. Again, it's just personal preference and it's cool if others love a loud show during dinner. I also find the variety of opinions here, and related discussions, to be enjoyable and not necessarily premature now that we have long-format videos of most of the ship.
Edit: I also completely understand others on here who have children with sensory sensitivities. At least most nights on the other ships their children can enjoy the dining experience. Here, they would be left out of the entire dining experience on most nights of the cruise. Sensory sensitivity is rather common these days.