Women's rights group All Women's Action Society (Awam) has condemned the six-month jail sentence meted out to Vivian Lee.
Lee was jailed for six months for a Ramadan greeting featuring bak kut teh (a pork dish), that was posted on Facebook.
Awam said while the posting was distasteful, it did not warrant such a sentence.
It added that the court did not take into account the impact of the case on "the fraying state of the ethnic relations" in Malaysia.
"It is the repeated abuse of ethnicity and religion as political capital by those in power that has strained relations among the different ethnic and religious communities in Malaysia.
"The imposed silence due to the 'infringement of religious sensibilities' of certain groups does not invite understanding, but instead causes even more division, and we believe that this court's decision furthers this damaging line of thinking," Awam said.
Lee also did not make the posting, even though she was featured in it, it added.
She is paying the price because the person who posted it, her then boyfriend Alvin Tan, is still at large, Awam said.
Tan absconded to the United States while on bail, and is reportedly seeking amnesty there.
Lee had during the trial testified that the posting was made in jest.
It was seen by critics as an insult to Islam.
The duo first caught the spotlight when Tan was expelled from the National University of Singapore for a sex blog detailing his exploits with Lee.