They probably used Microsoft Office as their inspiration on how to create a user interface that makes it difficult to to tell the difference between UI and data

They probably used Microsoft Office as their inspiration on how to create a user interface that makes it difficult to to tell the difference between UI and data. The flat UI's have their use cases but mostly they are just a bandwagon that all cool-kid wannabes are jumping on, without really caring or understanding that a UI is supposed to make things easier and less confusing, not the reverse.