“That’s why they make vanilla and chocolate ice cream” (i.e., people have different tastes)

“That’s why they make vanilla and chocolate ice cream” (or, “That’s why they make chocolate and vanilla ice cream”) means that not everyone likes the same flavor and has the same taste. A similar expression is “different strokes for different folks.” The words “ice cream” are sometime left off the phrase.
 
The phrase “that’s why they make chocolate and vanilla ice cream” has been cited in print since at least 1975.
 
     
19 August 1975, Wisconsin State Journal (Madison, WI), “Freedom Train visit,” section 1, pg. 10, col. 1:
The train has been praised by many as an entertaining and informative capsule look at the past 200 years of Americana. It has been condemned by others as a commercialized collection of trivia that cheapens the bicentennial celebration.
 
Well, that’s why they make chocolate and vanilla ice cream.
 
1 July 1980, The Capital (Annapolis, MD), pg. 7, col. 5:
And thus, my apologies. That’s why they make chocolate and vanilla ice cream.
 
Google Books
A Liberty Primer
By Alan Burris
Edition: 2, illustrated
Published by Society for Individual Liberty, Genesee Valley Chapter
1983
Pg. 230:
A blue sweater is not the same product as a red sweater, especially if you love red and hate blue. And that’s why they make chocolate and vanilla.
 
15 December 1983, Lexington (KY) Herald-Leader, pg. C1:
“But that’s why they make vanilla and chocolate—some like one thing, others like something else.” 
   
27 September 1990, All Things Considered (National Public Radio), letters:
And KG Hubert goes on, “Well, as the saying goes, that’s why they make chocolate, vanilla and strawberry.”
 
Google Books
Who calls the shots on the New York stages?
By Kalina Stefanova-Peteva
Edition: reissue
Published by Routledge
1993
Pg. 127:
RICHARD JAY-ALEXANDER
I can’t worry about critics because they have opinions and they are their opinions. That’s why they make chocolate and vanilla: taste is a very personal thing. You may like chocolate; you may like vanilla, but both can exist.
 
Google Books
Good Money: A Guide to Profitable Social Investing in the ‘90s
By Ritchie P. Lowry
Edition: reprint
Published by W. W. Norton & Company
1993
Pg. 81:
As Boston-based radio talk-show host Gene Burns is fond of saying, “That’s why they make chocolate and vanilla ice cream.” Different people come to different conclusions about what is more or less important.
 
Google Groups: rec.arts.mystery 
Newsgroups: rec.arts.mystery
From: Teresa

Date: 1998/03/14
Subject: Re: Peter Wimsey BBC Productions
 
I guess this fits into the “that’s why they make vanilla and chocolate” category. I thought the actor was very good- and captured many of Wimsey’s psychological traits wonderfully.
   
Google Books
Peanut Butter and Jelly Management:
Tales from parenthood lessons for managers
By Chris Komisarjevsky and Reina Komisarjevsky
Published by AMACOM Div American Mgmt Assn
2003
Pg. 87:
It was a wise person who said: You know why they make chocolate ice cream, don’t you? Because not everyone likes vanilla!
   
25 March 2005, Lowell (MA) Sun:
That’s why they make chocolate and vanilla, as the old saying goes.
   
FOXNews.com
Inflation Is the Boogeyman
Monday, June 26, 2006
By Susan C. Walker
Stocks or bonds? Coffee or tea? John or Paul? We’re all different – that’s why they make vanilla and chocolate ice cream. Different strokes for different folks. One person’s trash is another person’s treasure.
   
Gotham Gal
Season’s Greetings
My father has a saying, “that’s why they make vanilla ice cream”.  Essentially the same as, that’s why they have horse races.  Everyone makes different choices, everyone has different tastes, everyone is just different. 
(...)
Yet, as I sat through the play, all I could think of is what my father says, “that is why they make vanilla ice cream”.  For me, I would have definitely picked another flavor. 
November 23, 2008 in theater