The definition of Discrimination is a action that denies social participation or human rights to categories of people based on prejudice.
This is not about denying certain people the right to vote this is about how if you live in California your vote is weighted more than a vote from new jersey.
This petition is showing how those people votes from example new york don't count as much as the votes from California and that we should all be equal or rather we could accept the fact since your from new york, you are less important.
This is a form of Discrimination and goes against the saying "All men are created equal"