The most valid reason I can agree with.
If this happens, there would be alot of drama in the meta board.
But the banned accounts are public. Information can easily be accessed by anyone from modlog, Loyce.club and bpip. Why isn't there any drama in meta yet?
If impersonation was such a serious thing here, then that means even inactive accounts would be much prone to this, but this is not even happening often and even when it does, the DT members can easily notice the impersonating account and tag it.
Ban information can easily be accessed by you and some other good users of the forum. The no-brainers will easily come up with abuse if it is directly displayed on the profile. Making small efforts to see the logs might be difficult for them.
Besides, theymos is not a fan of implementing much things that third party tools can handle.
DT members will surely discover impersonation, but it will take some drama before it will be discovered. This is because the banned account won't immediately raise alarm, unless by creating an alt.