No where in the ancient shastras or the vedas or in any other scriptures we find that the marriage is symbolised with Thaali. It was a later development to depict that a woman is married that such a symbol was instituted.
Regarding the isms and the forward /backward castes, i think we have come very far away from all those things and we chave to put all those things behind us. Today all are given equal opportunity in all spheres. To be complete as a person and without provisions, we shoule see that only merit shines. Unofrtunately even now we find that "CASTE" is used to get priviledges. Those who speak, fret and fume anbout this division are those who are in othre words fanning the system of division.