Percentage buffs do not stack additively. They are not lying, they are following the rules mechanics that have been laid out.

You're being doubly selfish. You want people to take more time on runs, and enjoy it less, so that yuu can enjoy it more. And you play a DPS. DPS don't get a vote on anything. Supply exceeds demand, and so DPS have no value, and therefore what you want carries no weight. If you want to choose how a FP is run, play a tank or healer. Those two roles have a say.