Why "intentionally". May be it was put there intentionally but leaving it that way was a mistake. I don't think that's a backdoor, just from the article.

I would say that both malice and stupidity of HP are well balanced in this case.

It doesn't say it was left there intentionally. We don't have (or this article does not give) information enough to call it a backdoor.

Accidentally leaving an open administrator account is a bug as old as time. I won't necessarily attribute it to malice.

That said, it's still a backdoor, whether it was left there intentionally or not. I'd have a hard time trusting HP products after this.