Why should there be one? The EAForum website works great on mobile. So my guess is that there is no EA Forum app because it's not needed / wouldn't be that useful, except perhaps for app notifications, but that doesn't seem that important.
I'd ask in more positive terms - e.g. "Would an EA Forum app be useful?".
You could also add some considerations of relevance.
There exists the EA Forum feature suggestion thread for such things, though an app may be a special case because it is a rather big feature, but I still think it rather fits there.
From which a recommendation comes to mind for people who want an app: add a homescreen shortcut to the website.
Web apps can do notifications these days
Another advantage of an app may be that you could download posts, in case you go somewhere where you don't have Internet access, but I think this is rare and not a sufficient reason to create an app either.