Calling it the RCB's "worst batting performance", Kohli said that "it really hurts".
The visitors were bundled out for 49, the lowest total in the Indian Premier League after the KKR, put in to bat first by Kohli, were all out for 131.
"After the kind of half that we had, we thought we could capitalise and chase it down. Reckless batting. I can't say anything at the moment. It was that bad. This is just not acceptable," said a visibly annoyed Kohli, who himself scored a golden duck.
The India captain, however, claimed he was distracted by a spectator.
"The sightscreen is very small here, one guy got up as the bowler was loading up, that distracted me. Still it wasn't a big deal. That was just one down," he said.
Kohli said the team needed to move on, leaving behind the poor show.
"We need to forget it and move forward. We're a much better team. We got 200 plus in the last game. I'm sure everyone realises what they've done wrong.
"You have to come out, show intent and back yourselves. I'm sure we won't bat like that again in the tournament.
"We're going back home for a couple of games. We've got back-to-back games, need to try and win those to get some momentum," he said.
Ravi Shastri, Virat Kohli stress on keeping No.1 Test spot
Captain Virat Kohli says no extra pressure after Ravi Shastri takes over as head coach
Virat Kohli on ‘much-needed break' with Anushka Sharma
Kohli leads in congratulating Mithali Raj
You don't need to tell Dhoni how to play, says Virat Kohli
Kohli breaks Tendulkar's record of most ODI centuries in chases
Kohli stars as India beat WIndies by 8 wickets in 5th ODI
Tendulkar, Kohli and Warne in James Taylor's All Time XI
Captain Kohli praises West Indies bowling after India loss
Dominant India look to outclass Windies in third ODI