The 24-year-old winger was targeted by a wave of negative comments after wearing the shirt before Monday's game at Villarreal.
In recent weeks, there has been widespread support in Spain for the people of Ceuta following more than 70,000 irregular crossings into the North African enclave from neighbouring Morocco in July.
Before kickoff at Estadio de la Ceramica, players from both teams wore shirts bearing the slogan "Todos somos caballas" ("We are all mackerels"). Caballas is a nickname for people from Ceuta.
"At no point was the shirt referring to the people of Ceuta used with a political purpose or as a sign of disrespect toward my people, the Moroccan people," Abde wrote in a statement posted on social media.
"It was a shirt with a social purpose, intended to support a community.
"That said, this is not an apology to anyone, and anyone who wishes to use this to question my love for my country is free to do so. I will continue to live each day with my head held high."
LaLiga and Real Betis both posted messages of support for Abde after his statement.
Born in Beni Mellal, Morocco, Abde moved to Spain with his family at the age of seven. Eligible to represent both countries, he chose Morocco and made his senior international debut in September 2022. He has since won 37 caps for the national team.