Sisko didn't commit murder. He gassed the planet, but IIRC there's no mention that the gas would be lethal, and the Maquis were able to leave the planet in any case.
Honestly, sometimes it seems like people deliberately distort the events of the episode just to serve their argument.
It is most definitely mentioned that the gas is lethal to the inhabitants.
And the maquis had little realistic chance to leave the planet.
The one distorting events is you.