Read it for yourself. Not only read it, look at the actions and behavior of those who were involved with the creation of the system and who have subsequently taken public action.
The white paper defines the system as absolutely scaling to SP in every portion of the network. All up votes are scaled by SP. Up votes are not prohibited from being applied to your own creation. If they were never intended to be, they would be prohibited from doing so. Moreover, the example implementation of a social network built off of the steem blockchain has self voting built right into the posting mechanism so you don't even have to wait until the post is complete to decide that you want to vote up your own post, and it's even set on by default.
Clearly, self voting was a deliberately chosen part of the mechanisms of play in the game defined by the steem white paper.
Don't think of votes as dividends – they have no objective value. Instead, think of votes as buying lottery tickets. But don't think of an individual vote as a single lottery ticket. Instead, one up vote is equal to a number of tickets equal to the amount of SP (in vests) that you own multiplied by your current VP (multiplied by whatever percentage of vote that you give, which isn't enabled by default on Steemit until you have more than 600 SP).
All of those lottery tickets get associated with the post that you've up voted for a week, allowing more people to either throw their SP (scaled by VP) into the lotto pool or to flag/down vote which essentially spreads their SP (scaled by VP) like antimatter across the SP which is been put in as votes, canceling it out. At the end of the lotto period, all of those vests are counted up from all of the posts of a similar age and a portion of the fixed lotto pool is apportioned out to each post based on the sum total amount of SP (notice: not votes) each possesses.
And then there is a really complicated step where those rewards are then further subdivided and split into generation awards and author awards, scaled based on order of voting, and a whole pile of other ridiculous gyrations which are too complicated for even me to go into here.
But the above effectively happens every day.
What you are swaying is not vested interest but it's inflationary value. It's raw "currency" minted from nothingness which rains down onto the vote pool, and the size of the bucket is effectively decided by how much SP has gone into up voting a given post.
(There's also part of the reward pool which is allocated to Witnesses first and foremost, but even there pool is scaled by the amount of SP that they hold as determined by the SP/vests described by the number of votes they have to be Witnesses. Again, this gets a lot more complicated really fast.)
The important fact is that everything is scaled by SP. The distribution of SP among the population of the steem blockchain is vastly uneven, to the point that it's really immaterial what people below the 50% SP mark (that is, individuals who collectively hold less than 50% of the SP on the entire blockchain) do.
In a very literal sense.
In that environment, given that it's not prohibited, and that it is actively rewarded, clearly self-voting is intended part of the system.
Does knowing that change your approach to how you allocate your SP on a daily basis? That's the real question.
(As an aside, making self voting prohibited mechanically would have had very little effect on the system because it is quite easy to pay for a new account, hook it up to a very lightweight bot, and simply delegate it SP from yourself to vote for yourself. Just as we have systems right now which take STEEM and SBD in exchange for gambling on the amount of interested parties willing to invest, we would have simply had more of those which were simply limited to single-user pools as cutouts in the case where the system prohibited self-voting.)