Sikhism was, essentially, a monotheistic and egalitarian religious movement that originated in Punjab at the end of the 15th century CE. But, as it faced the outbreak of established authorities, it eventually transformed them into military movements, in which, religious harmony certainly played an important role.
Guru Nanak established a united community of followers. He made rules for Sangat and appointed his successor; a practice followed by later Gurus. This was the beginning of religious solidarity. His successors had many run-ins with the Mughal authorities- mostly on issues such as exploitative agricultural relations, during which religion was deployed as a rallying point for many conflicts by both sides.
Finally, the 10th Guru, Govind Singh, compiled the Guru Granth Sahib and established a corps of the Khalsa Panth, the devout religious-militarist body. These institutions served as rally points and eventually established regional independence movements and Misls by the mid-18th century.
Thus, the religious symbols indeed served as a rally point for Sikh solidarity.