Aren't Mass, Conn, Iowa, Vt, N.H., and Maine hypocrites for not allowing plural marriages?

If states like Iowa, Vermont, Maine et al can legalize same sex marriages as a civil rights and personal choice matter it should extend that to those who have an untraditional marriage that doesn’t encompass same sex people just several hetero women with one hetero male. Isn’t it rather two-faced to champion one group outside of traditional marriage but not stand up the same way for another? If you are taking religion away fro it an just making it about personal choice between people in love what reason is there to favor one and deny the other?