Referee Mateu Lahoz sent Sanchez a second yellow card for catching Fabinho with his follow-through moments after Lautaro Martinez had blasted Inter back into the last-16 tie with a thunderbolt effort at Anfield, cutting the Serie A side's deficit to 2-1 on aggregate.
The Chilean was enraged by the decision and refused to leave the field for several minutes, during which Inter coach Massimiliano Farris was sent off, but Klopp said Sanchez was lucky to be on the pitch at all by the time of his dismissal, having only received a yellow card for a knee-high challenge on Thiago Alcantara earlier in the game.
"I don't understand why we have to talk about the red card," he remarked. You don't win the ball if you can only win it by putting an opponent in danger while doing so. Both players will be harmed if Fabinho goes in with the same intention, with his leg out.
"I think he was lucky he didn't get a red card for going in so high on Thiago onto his knee in the first half." Passion is wonderful, but if it leads to these kinds of things, it isn't helpful."
The defeat broke Liverpool's 12-game winning streak, and while Klopp expressed disappointment at the conclusion of the run, he was philosophical as he pondered where the Reds can afford to lose.
Regardless of the outcome, the German believed the scoreline could have been different if his team had converted more of their clear-cut chances, with Joel Matip hitting the post and Mo Salah also hitting both posts.
"The art of football is to lose the correct games - I still despise losing, but if there was any game to lose, it was tonight since the essential goal was to get through, which we did," he explained.
"It's not that I'm overjoyed; I'm glad we got through because we thought the draw was challenging and that we deserved it over the two legs."
"We had some challenges, one of which was the opponent's quality; they are a very talented team." However, we still had chances to score but failed to do so. I didn't like our counter-press because it forced us to chase the scenario when we lost the ball, which was not what I intended.
"However, you must acknowledge the opponent's quality in the end." We could have won the game if we had taken advantage of our opportunities."
After securing a 2-0 lead in the first leg at the San Siro, Mo Salah said Liverpool may have been complacent going into the second leg of the last-16 tie, and vowed his team will learn from their first setback since December to bounce back in the championship chase.
According to BT Sport, he said: "We dropped a game that could have given us an extra boost. Perhaps we were overconfident in the back of our minds; it's a good game to take that in, learn from it, and go on.
"It's always crucial to win, but things happen, as tonight when we struck the post three times and squandered other opportunities. However, it isn't in the league, and we have already qualified.
