Days after he announced he would be leaving at the end of the season, Alexander-Arnold started Sunday's 2-2 draw with Arsenal at Anfield on the bench.
And when he entered the fray in the second-half, he was greeted by boos by a section of the home support.
Asked about the reaction afterwards, Slot went into detail over the situation.
He said: "I said to everyone that asked me that question that it is a privilege to live in Europe, where everybody can have his own opinion and everybody can express his own opinion. That is something we saw today as well. A few of them were not happy with him. I think all of them are not happy with him leaving the club. But a few of them showed it in a way that they booed him. And a few of them clapped.
"The only thing I can say about it is that I owe it to the players and to the club and to the staff – for everyone who worked so hard for us to win a game of football – to try to do that. And if we are, after 70 minutes, 2-2 and Conor (Bradley) can’t continue and I have a world-class full-back on the bench, I bring him in.
"And I think it’s a big compliment for him because you can understand how mixed the emotions were in his head probably as well; that you bring in a performance like that tells you why I think, why everybody thinks, he is a world-class full-back. Because with him we were quite close to winning this game, and that’s what I owe to the players in the dressing room that work so hard every single day: to make decisions to try to win the game."
Do I feel sorry for Trent?
Slot was also asked if he had sympathy for the player, who has spent his entire career with the club.
He continued: "It is definitely difficult for him because I think he said himself how difficult it was to leave this football club. And that is something that is important for us to hear as well, because we have to make it as difficult as possible. And fortunately for us many stay, like Virgil (van Dijk) and Mo (Salah).
"Trent made the decision to go. But it is the way you want to look at it; I don’t know, I haven’t asked him but maybe he is positively surprised how the reactions were today. I don’t know because I haven’t spoken to him, but it was clear they were mixed reactions so it wasn’t all negative.
"And as it went onwards, the moment he had to take a free-kick everybody was cheering for him to score – and he was close. So I am not even sure if he has negative feelings about today. Maybe, maybe – but again, I haven’t spoken to him – it’s not even as negative as you think it is."
Drop Trent?
Slot was also asked if he will consider leaving Alexander-Arnold out of his final two matchday squads of their title-winning season.
He added: "The thing I consider is I want to win a game of football and if we think we can win this one with Trent, I owe it to his teammates and to the fans, because they hired me to win as many games of football as possible. If I think there is a better chance of winning it with Trent, I will.
"If I think – which I don’t – that it is a distraction or whatever can happen for us not to play a good game of football, then I might, might, might make another decision. But I think Trent showed today why I brought him in because he was very close with a few fantastic crosses for us to win the game."