On one hand, excessive griping about a variability of a few hours to a day can be over the top.
On the other hand, it does make SCEA look incompetent and incoherent. It does inconvenience the end users a bit too much.
The frustration is understandable in that, downloading bigger digital products isn't instantaneous. Bigger games on PSN can take most of a day for many users. That goes for bigger Vita games too.
Most people's time isn't disposable. Adults who play games usually have to budget and juggle their time if they're devoted to the hobby. So, for example, the fact that XBL updates like clockwork at pre-dawn hours on the same day each week, does allow folks to schedule stuff. Going to download a big game? No problem, set it up before you go to work. It'll be there when you get home.
Totally random update times screw with the end user's ability to make their purchases and get going. For a lot of folks, the frustrating SCEA digital management can result in them actually getting to use said digital downloads near the end of the week, not just a bit later on Tuesday.
These are entertainment products and people would like to get their goods when it's convenient for them. Dicking about with the customer's time is how you lose customers.