I think that the love for both the Bengals and Falcons boils down to "Loss less from last year than everyone else."
49ers: Injuries. Seahawks: Injuries. Packers: Injuries. Redskins: Lucky to win division, will regress to mean. Vikings: Even AP can't stay that good this year; the rest of the team isn't AP.
Broncos: Injuries/suspensions. Ravens: Half the team left. Texans: Not good enough last year, no upgrades. Colts: Absurd luck/motivation; won't repeat. Patriots: Injuries/jail.
Personally, I hate those sorts of "Who lost the least?" comparisons.
A) Luck regresses to the mean. I would rather have my bad luck now and have time to adapt than in Week 7. (Admittedly, some teams will never get hit with bad luck this year.)
B) I would rather root for a strength than the perceived absence of weaknesses. E.g. There's a damn good chance that saying "The Patriots offense is in shambles!" will be regarded as rank stupidity in a month, yet I see a lot of people suggesting they aren't a contender, because, what, Belichick hasn't unveiled his pre-Gronk plans? Seriously?