Fanbyte is reporting
“It tested horribly. When playtesting groups received the game, the feedback to the development team was brutal. The target audiences Nintendo was hoping to hit — families with children — found the games boring; many didn’t even want to play through entire rounds. In the Bingo example, one player would use the joycon to mime digging out a number before reading it off the TV screen — a process that playtesters reported as tedious.
The main mode of the game, the Team Battle Mode, pit at least two teams of players against each other in various minigames. This mode prominently featured Horse, who would give color commentary during the games. During the localization process, sources started calling the game “Horsesh*t” as shorthand.
But no one expected Everybody’s 1-2 Switch to test quite as badly as it did. Different trusted employees within Nintendo were raising alarms that the game released as-is would damage the company’s reputation as a great software developer.”