That is very standard legal. If they did so, the impending class action would already be over.
I wouldn't be surprised if that blog post cost them well into 6 figures for legal fees. And that it took the full week to draft and approve--it is probably the reason this announcement took so long to emerge.
True, they are different probably because this (the Japanese announcement) is from Sony Corporation, and the link in English is probably from Sony Corporation of America.
In Japan lawsuits are less common, and an apology is expected even if it's not your fault, so it shouldn't hurt their legal defense if they apologize. I think it won't be interpreted as an admission of guilt like it could be in America.
We sincerely apologize to our customers and other parties who are affected by the continuing service impairment of the Playstation Network since April 21st.
> "We thank you for your patience as we complete our investigation of this incident, and we regret any inconvenience."
Sony apologizes only to Chuck Norris.