i agree, you could listen to the Scherzo in most of this works, and find them quite interesting. But, isn't that a stupid/foolish/ignorant thing to do? Bruckner didn't intend to write just one movement, did he? And the people who are familiar with his music knows that his themes are closely related and often re-appears somewhere else in the symphony, much in the tradition of Beethoven.
So, take the 8th for instance, let's say you just want to listen to the scherzo, because it's the shortest part of the symphony (for people who have the attention span of a teenager, the other movements are usually not very "interesting", too long). It's a nice scherzo, but what does it mean? German Michael? still makes no sense, it really doesn't, especially with the not so impressive opening theme, and the constant repetition. Well, you would've understood this movement better, had you kept on listening to the adagio and Finale, where you notice that the opening theme in the scherzo is in fact the same exact thing in the next two movements, and it shows up at the glorious coda too, of course, you wouldn't know this little insight if you skipped tracks and just listen to the "easier" movement.
If you are one of those people with short attention spans, or just can't sit through a rather long symphony, then Bruckner is not for you, you should instead try some of Strauss II's charming polkas (assuming that the waltzes are too long and tedious).