In any event, neither a blog nor Wikipedia would likely be a "primary source". Maybe something like a driver license would be a primary source.
It could be that you have a "philosphical objection" to "copy-pasted crap and artifically inflated content". I wonder if Google could have a role in encouraging the continued existence of this stuff. The effective opacity it creates seemingly justifies having an entity like Google.
Even when I entered the actor's name plus the term "age" and was redirected to the Wikipedia search results, I could still see the actor's page as the third result and his date of birth in the summary text.
As for why anyone would want to search some things using Wikipedia versus Google, I can think of a few reasons. I cannot speak for other users however.
I have a script I wrote to search Wikipedia from the command line. For those who care, one can strip out "X-Client-IP" from the returned page html before opening the page in a browser.
It's also another matter that so much of the internet is now filled with copy-pasted crap and artificially inflated content that it's actually hard to find what you are looking for on the so-called primary source webpages. If I want to find George Clooney's age, I don't want to sift through a 2000 page ad-ridden Page3-esque gossip blog about him.
At the same time, when I want detailed info about something, I will go in and try to read through the primary material.