Demba Ba seems like a good sort. Although he's not the most popular striker amongst Chelsea fans, who seem to have repaid the vitriol they didn't direct towards Fernando Torres after his first season with interest now that they have a less pretty centre forward to hold in disdain, Ba still scored a few important goals last year and offered the club an option they didn't have before his arrival from Newcastle. And also he's quite sensible sounding:
I think we need competition and we welcome the best players in this club. More competition is going to make me better anyway. All players want to play, not only centre-forwards. We will all work in the same direction, for the club, to try and win the games. I will stay.
Is Demba Ba good enough to lead the line for Chelsea? No, probably not. Is he good enough to be a third choice centre forward? Definitely, and I think he knows both of those things. It's rare to find someone content to keep improving and willing to help out when he can, and considering that Ba's on a very cheap deal, there's no reason not to be happy he's around.
Then again, most people were mean to Salomon Kalou as well, so maybe Chelsea supporters just don't like backups very much.