The right-back was met with boos at Anfield after coming off the bench against Arsenal, following news of his planned summer move to Spain.
"There's no right and there's no wrong. Everyone's entitled to go in the stadium, they pay their money to watch their team, and they're allowed to say whatever they want within reason,” Pennant told talkSPORT.
“They're allowed to clap, they're allowed to boo, they're allowed to cheer. So you can't tell someone not to do something.
"Would I do it personally? No. It's not going to help the team, because Trent and all of them team-mates have been on a crazy journey for multiple seasons, have won multiple trophies together, it's like a family, so if you know what one of your fellow colleagues has put himself through, in training, winning games, scoring last-minute goals, putting it all out there for you, and then to receive boos, you feel it as well.”