be (all) for (someone or something)
To support or be in favor of a person, group, or effort. If management is considering adding a gym to the building, I'm all for it! I respect your opinion, but I'm for the other candidate. I don't know about the rest of you, but I'm all for going on a hike!
be for someone or somethingand be for doing something
supporting or in favor of someone or something. I'm for abandoning the scheme. Mary is running for office, and the whole family is for her.
To be in favor of something or someone: I'm definitely not for cutting down the trees; we need the shade. Are you for these candidates, or against them?