No, they are comparing WW sales of Deadly Creatures vs Japan only of Okami for PS2.

According to Wikipedia, the PS2 version of Okami sold 200K in NA and 60K in Japan by 2007. We don't even have Euro numbers and legs improved sales. I bet it did around 500K on the PS2 a lone with legs.

Deadly Creatures only sold 160K.

hmm okay that makes more sense.

Do PS2 owners tend not to buy 3rd party games?  Because it actually bombed there first...

All we know about Okami PS2 sales are what it did in Japan and first month in the US.  Posted this a couple years ago when Okami Wii came out, was in reference to some Capcom guy saying Okami PS2 had done 270k.

"Ok, I did a little looking around, and it seems that 270k number for Okami (PS2) is probably not worldwide.

In the Media Create top 500 2006, Okami sold 142,676.
In the 2007 list the "PS2 the Best" release sold 50,890.
For the US, NPD had it at 86,676 in September.

So that already brings us to 280k. Also considering the quote was "That 270,000 figure is a very organic figure. Okami's day-one figure was nowhere near that," It would seem unlikely that he is talking about worldwide figures if the first day was nowhere near that.
Even if the trackers are off it seems impossible that they would be so off that they would end up with a greater amount from one country one month in another country."

And here are some links
Media Create Top 500 2006
Media Create Top 500 2007
NPD September

EDIT:  Actually it seems Okami kept on trucking in Japan.  Doing 38,541 in 2008 and 37,290 in 2009.  There may have been some adjustments though, 2007 to 08 total doesn't match, but 08 to 09 does.  That brings the best release to 140,580 and the total Japan plus first month US to 367,932.  Throw in continued American sales as well as European ones and the PS2 version has probably put up some respectable numbers.  Especially if the legs were like Japan, the PS2 version actually outperformed the Wii version in 2009 in Japan (though of course it had the whole year to sell).

Media Create 2008
Media Create 2009

Oh wow so it did do pretty well for itself.

Another issue that plagues these, "on the margin" type titles is piracy.

It may be that the PS2 version of Okami simply had quite a few copies pirated, it wouldn't have been too surprising. 

well look at all the niche and screwy titles from third parties that have been hits on the HD twins, Grand Theft auto, resident evil, Bioshock, devil may cry,games I"ve never heard about and aren't mainstream shooting games

heck the HD twins sold an obscure game like street fighter 4 and the wii could only move respectible numbers of huge established franchises like Tatsunoko vs Capcom,  who hasn't heard of tekkaman

amd look what happens when developers go out of their way to add features, in Madden wii owner got a great new art style and sales tumbled, SIlent hill seems to be selling better on the wii than HD twins so it doesn't count, and tomb raider featured extra bugs and glitches and it only sold 1/3 of the copies that the ps3 moved, look at PES soccer, wii owners get a longer wait and how do they reward konami, by buying other versions,

and don't bring up huge flops on the HD twins like GOlden Axe beat rider, bionic commando,  Dark Void  stranglehold or any other high budget game that sold porrly the developers intended them to be flops and gave them huge advertising budgets because they wanted the consumer to know to avoid them

I did my part by buying the game.