Planet13 - 6:55 am on Feb 11, 2011 (gmt 0)
Because people want to believe that running Xrumer is the key to internet riches.
It might NOT be the key to internet riches. And many people in those forums will certainly lie about its efficacy.
However, on these webmasterworld forums you will find many webmasters who were knocked out of the top spots by people scraping content, using Xrumer and spamming forums, blogs and profile pages. So, while it may not be the magic key, it certainly has dethroned a lot of "legitimate" web sites from the top spots.
In fact, if it weren't so effective, why is google re-dedicating itself to fighting spam?