"The desire to become a superhuman cannot be separated from supremacist ideals. Anyone with that serum is inherently on that path."
Zemo was right about this.
They've been experimenting on people with that serum for decades.
First, the Red Skull injected the serum to himself and it resulted with the face of his skin burning off since the serum wasn't perfected yet. He didn't even mind it, and despite going against the orders of Hitler, he continued his work with the Tesseract until Steve took it with him when he buried his jet into water.
The second experiment was Steve. It was a shocking choice since the US wanted someone big and strong for the experiment, and not a sick, skinny guy like Steve. But as we all know, Erskine especially wanted Steve because he was a good man, not a perfect soldier. Since the serum enhances what is already within, Steve was able to come out of the experiment with no side effects. And he was the only one who didn't get corrupt.
The third one was Bucky. Now his case was a bit different than the others. He got injected without his permission. They had already started to use him as a test subject when he was captured by HYDRA before Steve rescued him from the facility in 1943. Later, when he fell from the train he was able to survive thanks to the serum. But there were side effects since his memories had been wiped out, and the serum increased his aggression as well. (for example, his brutality in fighting) Also, even with the serum, HYDRA couldn't save his arm.
The fourth was Isaiah Bradley. He got the serum, just like the rest of them, and was sent to Korea to take down the Winter Soldier. He failed his mission but was able to almost rip his whole arm off. Then, they imprisoned him for 30 years because he was a super soldier. He was experimented on both by the US Government and HYDRA at the same time. We don't know much about his side effects but I don't think he survived all of that with no damage. Later, the CIA got his blood samples and Nagel used them to make more serum with it.
Fifth experiment: In 1991 HYDRA assassinated Howard Stark in order to create more super soldiers and start the Winter Soldier Program (which I always wondered, where the hell did Howard get these from? CIA? Did I miss that part? Someone enlighten me, please.) Now, these subjects were stronger than Bucky because HYDRA didn't use Vita Radiation (Howard Stark used this to stimulate growth and also "stabilize" according to Peggy Carter) But these new serum made the soldiers even more aggressive and they weren't easy to control. So when one of them attacked a HYDRA agent, the others followed him but they were brainwashed and frozen in the end, just like Bucky. After Zemo found out about Siberia, he killed them all in their sleep.
Sixth experiment: There was a new experiment in 2001 under Ross's command. They basically added Gamma Radiation along with the serum (hey Bruce Banner!). After that failed attempt, they injected Emil Blonsky a variant serum with Banner's blood in it. Long story short, the side effects were huge and not pretty. He turned into the Abomination.
Seventh, you'd think they would learn their lesson but no. HYDRA created a new serum in 2013. This time it was mixed with Extremist, Gamma Radiation, and the Chitauri technology. As if they worked perfectly before. They called it the Centipede Project. (Agents of Shield fans would know more about it.)
Eighth was the Flag Smashers. They injected the serum themselves. There are 8 injected Flag Smashers in total. Karli in this case doesn't care about who she kills as long as it serves her ideology. She's blinded by her ambition and she's not afraid to get her hands bloody because she knows she is doing the right thing. Her followers believe that she's leading them to freedom. To a world that has no boundaries, a free world where there are no countries to separate people from each other. No governments. No patriotism. One world. One people.
The Ninth, we've seen it coming. John Walker managed to take one of the serums before Baron Zemo crushed them all, and he used it to inject himself. We'll see the rest of the side effects in the upcoming episodes but I think we all know he's definitely not the next Steve Rogers.
Now, why did I list all of these? Back in 2016, I could never imagine myself agreeing with Baron Zemo but he is right folks. There hasn't been another Steve Rogers. He was the only successful experiment. The others were either corrupted by the nature of the serum, or they were blinded by the power that comes with it. Or they were just not the right choice.
Walker is a great example of this. He was given the title of Captain America because he was a brilliant soldier. Not because he had a good heart. He was the exact kind of guy that the government would want to have on their side. He was the captain of the football team in high school, then became the first person in American history to receive Three Medals of Honor and he had an incredible military career. This guy was a born leader.
And yet, since the beginning of the show, he's been struggling to fit the perfect image that the people want. The perfect Captain America the US Government wants him to be. He knows he can't be the next Steve Rogers and that has been eating him up ever since. He didn't have the serum which made him vulnerable since he was basically a normal soldier. He wanted to have Bucky and Sam on his side as his wingmen. His enemies weren't scared of him. His ego was crushed from the beginning. He wanted to be in control. He didn't just want to be respected, he wanted to be afraid. He was desperate for more power and it blinded him. He is one of the supremacists Zemo was talking about.
Lemar was the last straw. And he finally gave in. He took all of his anger from Nico. He didn't care that he was killing him, it probably wasn't the first time he got his hands bloody as he mentioned about the ways that they used back in his day of service, earlier in the episode.
When he was standing in that square holding the shield which was covered in blood, it made me think of all the other experiments that the United States is responsible for. Honestly, they started this nightmare, and just because they got lucky with Steve Rogers (thanks to Dr. Erskine) they kept pushing to get another perfect super soldier.
And I can't wait to see how they'll clear all this shit since the people all around the world are going to see how imperfect their new Captain America really is.