I think it's more the fact that Sega seems to fuck up a whoooole lot with regards to their image.
I would say that's a by product of it, because these people take more note of it now, but where does the myth of Sonic being hold right to win by many comes from? Just looking at the first stage of Sonic vs the first 13 of Mario proves which is closer to the hold right for win comment.
I do think SEGA has digged themselves in a hole, but a lot of the rose-tinted Dreamcast glasses a lot of these media outlets wear are mostly fake, like Dreams Dreams never being in the Saturn version of NiGHTS, or Jet Set Radio first appeared on the Xbox and well, it's really endless. They just say it to establish more credibility.
Yes their flagship franchise is in the toilet, but then you have stuff like Virtua Fighter, Football Manager, Total War etc all overlooked, at least when it comes to American media, here in the UK apart from Sonic the Hedgehog's sad decline in form, the press is often a lot more positive towards SEGA due to those games and stuff like The House of the Dead, Virtua Tennis etc I suppose it does not help SEGA probably have more games that appeal to Europeans than Americans too.
So yes, SEGA have dug themselves into a hole but I think it is not helped by people who never owned a Master System or Mega Drive who populate the majority of American video game journalists, evidenced by how everyone "copies" Nintendo. At least in terms to their overall history, it's often overlooked in the American gaming media industry.
Not that it matters at the end of the day, they are opinions and people here in the UK media are also biased in favour of SEGA, such as Silver 06 not getting as much as a bad grade as it should have.
But it's not like this forum or people here aren't guilty as well, look at how people trash EA, Activision etc when in reality they make some bloody brilliant games that get ignored.
Of course they are, but at the end of the day none of us are paid to review games. Although I think people should also note Game Informer is owned by GameStop.