Michael Laudrup elected to rest several players for the trip to Anfield ahead of Sunday's Capital One Cup final but Vorm says its display was not worthy of the Reds' stadium.
Steven Gerrard scored a penalty in the first half to give Liverpool the lead before Philippe Coutinho, Jose Enrique, Luis Suarez and Daniel Sturridge all found the target after the break.
"We owe the fans an apology because they travel all that way and we play like that - it's a disgrace," Vorm told reporters. "I've played a lot of games in my career already but this is probably the worst.
He added, "As a team you win and lose with each other, but when you have the privilege to play at Anfield against Liverpool in front of their amazing supporters, on a nice pitch, in good conditions and you play like that then you don't deserve to play at Anfield.
"We showed this year what we are capable of against the big teams but our mentality was so poor.
"I hope it's just an accident because we could have lost 10-0 and if you play like that against smaller clubs we will get beat."
The 29-year-old hopes Swansea will respond when it faces Bradford at Wembley but admitted that the heavy defeat would not serve their preparation well.
"I hope it's just this once because we have a final coming up and it does not help your preparation to have a game like this," Vorm said. "I hope it's a wake up call for next week but don't think we needed this.
"Everybody has to look in the mirror and ask if they gave 100 percent and what more they could do better next time. We mourn for a couple of days and be sharp and fit for the final."