Back-scratching, yes can be a problem - but it is different from autovoting.
Auto-voting is just a tool. Used effectively it can benefit Content Creators. I know many people that use auto-voting to provide consistent rewards to Content Creators that produce quality content.
I use auto-voting myself and I've lost count of the number of Content Creators that have thanked me for supporting them. I do not have the time to read every word of every post they make. But I do I review their blogs periodically and adjust my auto-vote, even removing my vote if warranted. Also I'm always on the look out for new Content Creators to add to my list.
I think it is important that we define the problems we see properly. Back-scratching, circle-jerking or whatever we want to call it exists and it is a problem. I'm not sure it can be completely irradicated but it can be mitigated. However eliminating or demonising auto-voting does not solve it. It is just as easy for a relatively small group of 'whales' to manually vote for each other as it is for them to auto-vote.
What doesn't scale so easy is trying to reward hundreds or thousands of Content Creators through manual voting, there simply aren't enough hours in the day. Auto-voting helps with this until we reach a point where larger Steem Power holders can run their accounts like a business and hire people to professionally curate for content. We're a long way from that point, so auto-voting is the best we've got to consistently reward good Content-Creators.