Went through support all the way until they got me a Samsung rep. They had me clear both cache and data for Internet app. This removed the AT&T bookmarks. Replaced them with a bunch of others, but they were deletable.
I had an issue with this on my Galaxy Note 2. Apparently some stupid "SmartWifi" app that AT&T thought prudent to install was the cause of the problem. AT&T doesn't let you uninstall it either. But I was able to disable it.
Sadly, I get alerts/notices, but no alarm. I want an alarm to sound...