"Nakakalungkot kasi ito ‘yung isang tao na hindi naman Pilipino pero inialay ang kanyang buhay for 27 years para tulungan ‘yung pinakamahirap nating kababayan," Robredo said in a radio show on DWIZ.
"Nakakalungkot na pinaalis siya dito sa atin. Mas Pilipino pa siya kaysa sa marami sa atin," she added.
The vice president recounted some of Fox's most important contributions to the communities she had been immersed with.
"Tinuturo sa kanila kung ano ‘yung kanilang mga karapatan sa paniniwala na kapag alam nila ang karapatan nila mas nasa posisyon para ipaglaban ito," Robredo said.
Fox left the country after the Bureau of Immigration denied the extension of her temporary visitor's visa and ordered her to leave the country on November 3.
The missionary nun was accused of joining "political activities" in the Philippines but she maintained that her participation in fact-finding missions and advocacy for social justice was within the bounds of her missionary work and protected by guarantees to free speech and assembly.
She was first arrested then released pending further probe by Philippine authorities in April.
President Rodrigo Duterte later said he was the one who ordered the investigation into Fox for supposed "disorderly conduct."
Robredo also expressed dismay over the reason why the missionary nun had to leave the country.
"Nakakalungkot na politika ‘yung naging dahilan. Nakakalungkot ‘yung pagpahayag ng saloobin parati kailangang pagbayaran," she said.
The vice president went on to give some reminders to government officials.
"Siguro paalala din sa atin, sa amin na mga pulitiko na pahiram lang sa amin ‘yung mga posisyon na hinahawakan namin ngayon. Dahil pahiram lang ito, ang nagpapahiram nito taong bayan. Ayusin namin. Hindi namin dapat parang kine-claim na personal itong karapatan," she said.
Furthermore, Robredo said she believes that Fox will soon be able to return to the Philippines.
"Tingin ko temporary lang ito, temporary lang ‘yung pagkawala niya dito sa Pilipinas... Tingin ko dadating ‘yung panahon na babalik din si sister sa atin at ipagpapatuloy ‘yung misyon niya para tulungan ang mga Pilipino," she said.
The National Union of People's Lawyers (NUPL) previously mentioned that Fox plans to come back to the Philippines once Duterte's term ends.
"She intends to come back in the Philippines as soon as President Duterte is out of power and another government more receptive of dissent and who recognizes missionary and human rights work is in place," NUPL said.