This seems like a lot of different people voicing different opinions and talking past each other. Roughly, I think you're jumping into the middle of a hypothetical conversation that went like this:

Person A: "It's bad that we throw people in prison for pot, and use possession of pot as a subtext under which to harass people, perform warrantless searches, etc. We should just legalize it."

Person B: "But it might be bad for children and teenagers if they get access to it"

Person A: "Okay fine, we legalize it for people over the age of 21, happy now?"

Person A could be said to have compromised or ceded-ground to person B here, even though they themselves might actually not even disagree.