You have to remember that when people are upvoting themselves, they are using their own steem power which they have either earned through SteemIt or have purchased. Either way, they have every right to use it as they wish.

Being able to upvote one's own content, whether it be posts or comments, encourages people to engage with SteemIt and to write more that they might do otherwise. I have not seen an increase in "junk" since the hardfork. In fact, things appear to be the opposite.

Also, when people see that an article or comment already has value they want a part of it. It's as simple as that.

I upvote my own content and also reserve some of my voting power to vote up people who comment on my posts or comments and also for other content I see on SteemIt. I see nothing wrong with this balanced approach.