It is because it breaks our development workflow. Imagine you are an accountant working on a financial report to the board which is purely a desk affair but frequently you have to go down to the warehouse and factory to manually count hard assets which should have been done by an internal audit team.
Imagine if you are working the cash register at the take away drive through window with a long line of cars waiting for their turns but you need to go to the kitchen to prepare the food yourself for every order instead of delegating that work to dedicated kitchen staff.
Anything that requires concentration and focus like maths or programming does not mix well with other equally time consuming and attention diverting issues like DevOps or taking support calls.
You have this mathematical structure and branching in your brains and your brain is spinning for pattern matching and what ifs scenarios and logical tests and you are forced to stop this momentum, suspend it in memory to attend to some DevOps concerns which require a different theater and orchestra to be set up in your brain only to be suspended again to load all the previous intricate programming context and re-familiarize your brain with all the twist and turns you had taken earlier and track where you are in that logical mesh.