They do tend to lose all meaning when there are hoardes of the blighters. I don't even pay attention anymore - when there was one stickied thread every once in a while I'd always read it, on the basis that it had to be important. I don't want to hide them - presumably some of them are still interesting. But they've become wallpaper.
Nothing to add on the question of stickies, but just want to observe how refreshing it is to have Android namechecked, rather than the usual wall-too-wall apologies for poor typing because of a "bloody iphone" or "bloody ipad"!
I don't think there is a way to hide threads on the app. It sounds like the process on our side that sends data to the app is not requesting your sticky preference. We should be able to fix that - I'll take a look at it.