Libertarians want to cancel social programs and replace with UBI so individuals determine how to spend their benefits. Socialists want to guarantee everyone a living wage but also want the safety nets.
Policy needs to be in middle. You need to enable people to self-manage. Must be ready to help them when there is a bad turn events. But you also need to have a humane way to deal with people that are incapable of taking care of themselves, for example mental illness. The way to handle that is guardianship, not other government programs that can also be individually mismanaged. Guardianship will surely be more expensive then UBI but it is the humane thing to do.