The use of aliases is normal practice and still happens as agents get harassed by irrational non-taxpayers.
I just spoke with an IRS agent last week that used an alias. She explained that a person she was processing collections procedures against threatened her family members and sent her pictures of them online. I don’t have a problem with using aliases to protect their children from attacks.
I’ve observed a similar practices by mental health professionals, especially females who have clients try to develop relationships with them. I’ve attended court hearings in such situations and understand that they need protection.
Anyone who chooses to work for the IRS deserves all the public scorn they get.