Why? They knew both men were leaving after the match so why should they give a shit? Also Lesnar was quitting out of nowhere so of course wrestling fans are going to hate him.
Crowd or not, the match sucked. There was nothing for them to get behind. They hated Lesnar for leaving and they weren't going to get behind Goldberg since they knew he was out of there. Then the wrestlers responded by standing there for two minutes.
But this isn't the territory days. Everyone knew they were both leaving and never coming back. Who are they supposed to get behind? What's their motivation to get behind Lesnar? Or root for Goldberg? And again, the match sucked.