If I ignore a user it hides their content on the forum from me. But it still shows it on the Dashboard page to me. Pretty sure also when I checked the ignored users profile page as well and search their posts, it even showed their posts there to me also.
I would have thought if you ignore a user and it hides their content from you on the forum, then it should be hiding it from you in other areas as well. And having the landing page set as Dashboard page, means you see anything they added on the forum right away displayed on Dashboard landing page, that is actually hidden from you on the forums