operating systems – Why semaphores lead to loss of modularity?

In this article Semaphores in Operating System and other articles on the internet, they have mentioned one of the disadvantages of semaphores is that it leads to loss of modularity. They further said that this loss is because of wait, signal operation preventing the creation of a structured layout of the system. I didn’t get what the creation of a structured layout means here and how the operations are affecting it. Also, let me know if there are any other reasons for the loss of modularity.