I think symbols just mean whatever the person displaying the symbol intends them to mean. The Crucifix is a Roman and pre-Roman method of punishment and torture, and was usually shaped like a "T" and low to the ground. The crucified were usually displayed at the gates of a city to show newbies what happened if they broke the rules of the city.
The Solar Cross represented the Suns annual path through the 12 personified constellations in many ancient religions. Among the stories of those religions included the Sun's death and resurrection throughout each year. These stories got all mixed together with the story of Jesus when the Roman Government made the Universal Religion. As an example, compare the Pagan celebration of the Goddess Eostre, with the Catholic (Universal Religion) celebration of Easter.