Leaving aside all the reasons why this policy is super dumb (which I'm sure others will cover quite adequately), I guess your IT department can't figure out how to create their own CA certificate and do SSL interception?
Yeah, I'm amazed and concerned that you have a security team so paranoid that they would make SuperUser read-only but apparently lack the ability to perform SSL interception. Considering the huge value the latter has in any kind of post-compromise scenario and, increasingly, to prevent compromise in the first place... there needs to be a real discussion about getting priorities in order.
There are many enterprise "solutions" that basically do this "out of the box". Yeah it shouldn't be done and a lot of employees are likely unaware that IT can see all of their SSL traffic but it's a big business.