They can't keep getting away with it

[...] basic human rights, like the right to vote [...]

Equality is the cornerstone of democracy.

Universal Declaration of Human Rights, Article 21.3:

The will of the people shall be the basis of the authority of government; this will shall be expressed in periodic and genuine elections which shall be by universal and equal suffrage and shall be held by secret vote or by equivalent free voting procedures.

Now explain "first past the post", gerrymandering, or the D'Hondt method.