It’s not the struggling artists, it’s corporations, lawyers and boards who are in favor of such a shortsighted law . Here’s the list of companies behind one of the lobbying groups pushing for SOPA (here are three links about the law). Now you know who to call:

ABC
AFTRA – American Federation of Television and Radio Artists
AFM – American Federation of Musicians
AAP – Association of American Publishers
ASCAP
BMG Chrysalis
BMI
CBS Corporation
Cengage Learning
DGA – Directors Guild of America
Disney Publishing Worldwide, Inc.
EMI Music Publishing
ESPN
Graphic Artists Guild
Hachette Book Group
HarperCollins Publishers L.L.C.
Hyperion
IATSE – International Alliance of Theatrical Stage Employees, Moving Picture Technicians, Artists and Allied Crafts of the United States, its Territories and Canada
International Brotherhood of Teamsters
Kaufman Astoria Studios
Macmillan
Major League Baseball
Marvel Entertainment, LLC
McGraw-Hill Education
MPA – The Association of Magazine Media
NFL – National Football League
National Music Publishers’ Association
NBCUniversal
News Corporation
New York Production Alliance
New York State AFL-CIO
Pearson Education
Penguin Group (USA), Inc.
The Perseus Books Group
Producers Guild of America East
Random House
Reed Elsevier
SAG – Screen Actors Guild
Scholastic, Inc.
Silvercup Studios
Simon & Schuster, Inc.
Sony Music Entertainment
Sony/ATV Music Publishing
Time Warner Inc.
United States Tennis Association
Universal Music Group
Universal Music Publishing Group
Viacom
Warner Music Group
W.W. Norton & Company
Wolters Kluwer

[Disclosure. I worked for or have been a member of various entities on this list over the course of my career.]
Source: the domino project