Irrelevant - the product page says otherwise and the game itself was explicit in telling you that a PSN account is required on launch.
They're changing all their documentation to match their new announcement: https://www.reddit.com/r/Helldivers/comments/1cjlnn1/sony_tr...
This is an official page where Sony themselves sell the game via providing voucher codes for steam. You can buy the game here without ever visiting the steam page. This clearly qualifies as false advertising.