I did as directed and created a new Administrator account. I logged in as the new administrator, but Parental Controls were NOT enabled. Neither were Parental Controls enabled when I logged in as the previous, original administrator. The one thing that did happen was that when I logged in as the new administrator and used Safari, the Bing redirect did NOT happen.
I would keep the new Administrator account and delete the old one except that would mean losing all of my saved emails
One of the manual removal instructions, which I had already read, somewhere send us to windows where the commands and selections that the instructions specify simply do not exist. I think the manual removal instructions were written a previous version of OS X, not High Sierra which is what I have.
The manual instructions also say somewhere that as a last resort, "reset Safari." This is supposed to get rid of all Extension, Plug-ins, delete all history, delete all cached data, delete all cookies, etc. etc. and reset Safari to "default settings." The instructions tell you to open Safari, select the Safari drop-down window from the upper left corner and then select "Reset Safari." This would be really nice except that there is no "Reset Safari" selection anywhere in Safari or anywhere else on the computer - I've spent over a week looking. It also makes me kind of distrust the manual removal instructions