If it came with the TV pre-installed, there's a good chance you can't unistall it. Luckily, you're not obliged to use it. It doesn't harm to have it installed.
What's the full model number of the TV?
The possible positive side of the story: if HBO pays Samsung to include that app, it makes the TV cheaper.
dittos hellp!!! frustrated HBO GO UNOPRATEABIE !!!