That's not why it is getting down voted, I believe.
Jobs influence over Apple's products went far beyond merely selling them well, and this was extensively discussed in the bazillion news stories and blog posts in response to his resignation as CEO, and those were heavily discussed here on HN and in other comparable forums.
Accordingly, I believe that many of the down voters don't merely disagree with the post, but believe that it is objectively wrong, AND feel that there is just no good excuse for a regular HN reader/poster being wrong on this.
Is it because people disagree? Because that isn't a reason to downvote.
It's a common and legitimate reason to downvote on HN, even pg has said so. I once disagreed with this practice but have changed my mind given it has been 'approved'.
And to say Jobs was a salesman because he didn't "design" any hardware is bizarre. He was the driving force behind the Macintosh and involved in almost every decision surrounding it, even if he wasn't the one with the pen at the drafting board. It's like saying Obama is merely a spokesman.
The downvotes are because his post is highly disrespectful in tone, and frankly ignorant in substance.
It would be just as accurate to call either Einstein or Feynman "just a physics teacher". The title, while technically accurate, fails to fully encompass the magnitude of the work.
If you are unaware of Steve Jobs' contribution to both hardware and software you are sadly uninformed, not just about Steve's life and work but about what it takes to create products that can change the world. I don't even own a single Apple product, but he has made everything I use so much better.
It seems accurate to say that Jobs was a salesman. He didn't design or write any software or hardware that I know of.