this motion insists on a one state solution.

Why?

Because a single state that doesn't discriminate based on religion and ethnicity IS the only solution that could possibly create lasting peace and justice.

As long as there's a Jewish supremacist apartheid ethnostate on or next to their land, no Palestinian will be safe.

Being a single ethnostate with several ethnicities being oppressed by the dominant one obviously doesn't help

Fixed it for you. Like South Africa before it, the solution is to overthrow the tyrannical apartheid system of government, not portioning out a tiny parcel of land next to it that the overlords will always scapegoat and vilify.

So what is the benefit? Why is it insisting on this?

See above.