Off contract in June, fullback Alexander-Arnold is said to have agreed terms with Real Madrid ahead of a summer move.
The news has led to a backlash from Liverpool fans, but the reaction has left Warnock unimpressed.
He posted to X: "Can’t believe the negativity directed towards Trent Alexander-Arnold and his potential move away from LFC. I’ve seen comments like 'he should be ashamed' and he’s 'not loyal to the club' are deluded.
"He’s entitled to make his own choices and challenge himself in a different league and different country. He’s won everything with LFC, been an incredible servant to the club and should be given a great send off by the fans."
