It's Dave Sim BTW. And what you're looking for (I hope) is here:
http://www.timemachinego.com/linkmachinego/dear-jeff-smith-from-dave-sim/
I have not included the whole text, not only is it lengthy but due to copyright issues.
Jeff Smith's letter to Dave Sim in response to the offensive content in Cerebus issue 186 is not publicly available, so the specific content is not known. However, it is understood that Jeff Smith was deeply troubled by the content and expressed his concerns to Dave Sim in the letter.
The Smiths was created in 1982.
The Smiths Is Dead was created in 1996.
Smiths Gore was created in 1847.
Smiths News was created in 2006.
Smiths Group was created in 1851.
Smiths Falls was created in 1823.
Smiths Falls Bears was created in 1961.
The Sound of The Smiths was created on 2008-11-10.
Three Smiths Statue was created in 1932.
Smiths Dock Company was created in 1810.
Smiths Station High School was created in 1918.
Smiths Grove Baptist Church was created in 1898.