Stallman ya ƙaddamar da manufar copyleft, wanda ke amfani da ka'idodin dokar haƙƙin mallaka don adana haƙƙin amfani, gyara, da rarraba software kyauta, kuma shine babban marubucin lasisin lasisin software kyauta wanda ke bayyana waɗannan sharuɗɗan, musamman GNU General Public License (GPL), lasisin software kyauta da aka fi amfani da shi.A cikin 1989, ya kasance ɗaya daga cikin waɗanda suka kafa League for Programming Freedom. Tun daga tsakiyar shekarun 1990, Stallman ya ɓatar da mafi yawan lokacinsa yana ba da shawara ga software kyauta, da kuma yaƙi da haƙƙin mallaka na software, sarrafa haƙƙin dijital (wanda ya kira shi da sarrafa ƙuntatawa na dijital, yana kiran kalmar da ta fi dacewa), da sauran tsarin shari'a da fasaha waɗanda yake ganin suna ɗauke da 'yancin masu amfani. Wannan ya haɗa da yarjejeniyar ba da bayyanawa, yarjejeniyar kunnawa, maɓallan aiwatarwa, dongles, kwafin binaries, da lambar lasisin mallaka. Tambaya: Menene Stallman ya yi yaƙi da lasisin lasisi? Tambaya:
yarjejeniyar lasisin software, yarjejeniyar rashin bayyanawa, maɓallan kunnawa, dongles, ƙuntata kwafi, tsarin mallaka, da binary executables ba tare da lambar tushe ba