Universal salvation is worthy of the condemnation it receives because it tells people that God won't judge sin and so it encourages people to ignore Christ and sin with impunity thinking they can game the system and live their entire lives in rebellion against God and then after they die all they will need to do is say "I believe" and will get into heaven. But God calls those who think that fools. And Christ said the following:
These people who Christ is talking about didn't even buy the full lie of universal salvation but thought that if they just impersonated a Christian a couple of times in their life that after death that would be enough to gain entrance to heaven.Matt 7:22 Many will tell me in that day, 'Lord, Lord, did not we prophesy in your name, in your name cast out demons, and in your name do many mighty works?'
Matt 7:23 And then I will tell them, 'I never knew you. Depart from me, you who work iniquity.'
But Christ tells them after death that He never knew them and tells them to depart. Where does Christ ever say that these people can come back to Him? He doesn't because they can't.