Yeah, I also think the person who wrote this has a somewhat distorted view on Seraphon (although I think he is right with the versatility. We are a pretty complete army).
I don't know which armies he plays or can compare Seraphon to, but especially the "shooty and tanky" bits made me think he is probably playing against a weird subset of Seraphon lists.
I mean: We have two "tanky" units IMO: Bastiladons and Saurus Guard.
If you have ever played armies like Ironjawz or Bonesplitterz and ran into an army consisting of Bastiladons and an Eternal Starhost, failing to kill a single Saurus Guard with 90+ attacks at rend-1 (and people playing against me have done exactly that) then you probably think Seraphon are a nigh unkillable army. There are people in my shop who fail to see the ubiquity of mortal wounds in certain armies so they think those two units are outright broken. Because rend-1 immune and rerolling a 2+ save is damn bad news for them then. But at the same time there are armies with such a high mortal wound output that they tear through those Guard like through paper.
Actually if you consider the 'meta' right now I guess Skinks are actually better "tanks" than Saurus Guard, since you get a lot more wounds for the same points, they work against mortal wounds about as good as against normal ones, they move faster, and they work outside of a bataillon.
Sure, the Bastiladon qualifies as tanky, even by pretty high standards. And yes he has a 20" rend-1 attack that does decent damage. But its attacks are fairly random, the range of 20" isn't exactly stellar, it is a 4+/3+ attack and he is 280 points.
...and that's probably our best ranged unit. Most of our shooting is pretty short ranged (the only one with longer range is the Stegadon and that 25" range bow rarely does a lot of damage), we don't have ranged units that shoot 30" or more, none of them has special rules to do mortal wounds, and we don't have artillery that ignores line of sight.