Because they're not as great as ska fans say they are. And it's somewhat of a backlash.
Personally, after SITB I just got sick of every song following pretty much the same format over and over again. I came to the realization that Kalnoky's lyrics were embarrassingly cheesy, every song features boring songwriting that goes nowhere, and an assholish fanbase that is probably the worst in the genre. The problem is we didn't notice this when it came out because of the hype. "A ska band that will get the genre noticed, yeah!"
I used to wonder why the reviews weren't as kind to SM as the fanbase, but I slowly learned why, and it's because of all the above. The problem is that most of us didn't see it at the time, but now it's clear as day.
I have nothing against any of them, and they are fantastic musicians, but their material is so novelty that it's just plain lost any spark it once had. Kalnoky needs to take a poetry class or two, since his lyrics really need the work. He should also stop writing the same basic song structure over and over but slightly changing a horn line.
People like Keasbey Nights because it's a young band trying to stand out by putting their best foot forward and trying their best. Not a band trying to sound deep by writing convoluted lyrics and using musicianship to mask poor writing. Say what you will of the musicianship on Keasbey, but the songs are all entirely different and the band puts it's all into it. SM stuff sounds lifeless in comparison.
That's all IMO.
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