This is why you need context when discussing things. Imagine discussing the politics of the penal system and someone butts in, "imprisoning people is bad by definition"... Ok man
Change your framing from butting in to sitting down with someone and trying to agree on the penal policy. "do we all agree that incarceration is bad, and should only be used when the alternative is far worse."
Do most people agree that affirmative action is racist? Should we ever allow racist government policy? If so, what are the limits for when the ends justify the means?
And that someone would be right and that's why it should be avoided as much as possible. Because people refuse to have this discussion, imprisonment is applied at a far larger scale than necessary.