Sure there's a difference. If you create a bunch of your own accounts to upvote a story, then all those upvotes collectively convey the following information: "One person liked this". (Worse still, that one person is the person who wrote it; so, near enough zero information.)
If you instead write something that lots of people upvote, then all those upvotes convey the following information: "Lots of people liked this."
Now, it's still bad that they "liked" it only because they know who wrote it and think he's generally interesting. The outcome for HN is probably still that what's on the front page doesn't match what's most interesting as well as everyone would like. But the problem is low-quality real information, not fake information. It's not bad in the same way at all.
If you instead write something that lots of people upvote, then all those upvotes convey the following information: "Lots of people liked this."
Now, it's still bad that they "liked" it only because they know who wrote it and think he's generally interesting. The outcome for HN is probably still that what's on the front page doesn't match what's most interesting as well as everyone would like. But the problem is low-quality real information, not fake information. It's not bad in the same way at all.