Why? Google is lousy for searching forums unless you're searching for an exact phrase.
Google does not have any direct concept of separation between posts. It can only approximate "search for these keywords in one single post" by preferring keywords that are in close proximity.
Proud reseller of little geisha dolls with big heads that wobble.
"Want to keep guns out of the hands of felons? Make fewer felons in the first place." --Vanya