You have to see the other side of the argument to properly understand. I play Minecraft a good bit with friends of mine, so I don't hate it by any means, but I can't help feeling bored with it for similar reasons - the goal of building a thing is a self-motivated goal that does not reward you with anything but the end product. For a lot of people, that's plenty reward, and that's great. More power to them for the ability to find the motivation to make cool things. But for some people (i.e. myself and some others) it's not so easy to self-motivate yourself to create something that ultimately just looks pretty. A number of us look to games to give us goals, and to reward us for working hard to reach them. It gives us an emotional through line and a sense of satisfaction we can't get from just... building something.
The kind of game a non-self-motivating type like me looks for is a game that, say... shows me a massive dragon. So I try to fight it, and it whoops my butt, making me feel compelled to get stronger so I can come back and win. So I go out, and I work hard, and I fight stuff, increase my stats, get better at the game, and finally go slay the dragon, which (hopefully) drops some kind of awesome item as a reward for all my efforts.
Compared to that, in the eyes of someone who doesn't self-motivate, Minecraft is (for the most part, yes I know there's a dragon but the game isn't about that) a game that doesn't show you anything. It doesn't compel you to grow stronger, or journey further. It just hands you a bunch of stuff (whatever you can find in the game) and says, "Do whatever." For some people, that's enough. For others, it's not a compelling enough reason to keep playing. And when there are other games with more structured approaches that actually provide goals to the player getting less attention while Minecraft enjoys massive popularity with a minimal amount of structure (if any, really), it's kind of hard not to be a little bitter.
tl;dr - I understand the dislike for Minecraft. It's not a perfect game by any means (is anything, really?). But different people are drawn to different stuff. So it has always been, and so it will remain.