He didn't pick a fight with anyone. He rightly described the situation on the ground in his country, and expressed his apprehension with making a deal with Putin given Putin's history of reneging of his seals with Ukraine. A history that has consistently led to the deaths of more Ukrainians. And when he called Putin a dictator, a terrorist, and a murderer (all truth accusations), that's when Trump lost his mind. He completely ignored the context and facts surrounding what Zelenskyy was saying, and acted like Zelenskyy had just attacked his best friend. Remember, Ukraine is supposed to be our ally, and Russia is supposed to be our adversary (and has been since the 50s). To put what happened on Zelenskyy is incredibly dishonest, and ignores the context Zelenskyy was speaking, and the objective facts he laid down.