The National Student's Federation (NSF) formed the shield at Swami Narayan Temple as part of an attempt to promote interfaith coexistence and cooperation among different religious and ethnic groups.
A member of the NSF describes the union as a "progressive leftist organisation" dating back to the NSF of the Ayub Khan era.
"When we showed solidarity with Shias at the Imambargah... it's only fair that as a group, we extend the same courtesy to all Hindus in Pakistan who face a lot of persecution of different kinds," General Secretary NSF Fawwad Hasan was quoted as saying by the Dawn.
"We are not religious fundamentalists who take religion into our own hands, that is not what we do," Hasan said.
"Society as a whole has to show change and be a part of that change. If you don't stand up for someone else's rights today, tomorrow you will also be targeted and there will be no one to stand up for your rights," he added.
Sectarian violence in Pakistan has been on rise with banned outfits like Lashkar-i-Jhangvi and Sipah-i-Sahaba Pakistan killing scores of minority Shia muslims.