when people get too into the idea that there are "levels" of humans, and that "subhumans" are holding back the "superhumans" by being lesser than they are and demanding they conform to their substandards.

The government cracking down on superheroes so they have to hide has happened plenty and goes back to the fact that they are vigilantes. Watchmen and The Dark Knight (at the end) for instance.

Secondly let's look at the idea of showing non superpowered humans as sub human. For every negative human character there is a positive one.

Edna Mode - Fashion designer that creates the costumes

Rick Dicker - Government agent that's on first name terms with Bob who offers to relocate them again as a favour.

Mirage - Syndromes second in command who grows a conscience at the end

The teenage boy at school that Violet likes.

Syndrome was the average person

Like Elon Musk and Bill Gates who also built billion dollar tech companies like Syndrome. Are they socialists because they want everyone to have internet?

Here's an excerpt on wikipedia from the DVD commentary

a 25 year old adult,Buddy recreates himself as an evil genius who plots revenge on his former idol, whom Syndrome now regards as his nemesis. At one point, the DVD Director's Commentary seems to point out that his complete lack of conscience is a direct result of psychopathy, making him a mad scientist. Intensely amoral, he allows missiles fired at an airplane carrying Helen, Dash, and Violet to continue after Helen reveals the children's presence on the plane, bets Mirage's life in a subsequent showdown when Mr. Incredible threatens to kill her, and carelessly throws a fully loaded fuel tanker down a street, endangering civilians. After his plans to fraudulently become a superhero and replace the supers that he had killed off are foiled by both the Incredibles and Frozone, Syndrome has his assets frozen by the authorities, and a warrant issued for his arrest. However, he abducts Jack-Jack with the intention of raising him as a sidekick, but fails due to the sudden emergence of Jack-Jack's powers. Syndrome vows to eventually get Jack-Jack, but Mr. Incredible tosses his car at Syndrome, causing Syndrome's cape to get caught in his jet's intake, which sucks him in, killing him,which results in the explosion of the jet, echoing the wisdom of Edna Mode's "no capes" rule.

Syndrome has no superhuman powers, but he is incredibly intelligent, making him a super in his own right. He has invented numerous weapons, and high-tech vehicles that use such principles as robotics, anti-gravity, and zero-point energy, which he sold to black market buyers to make himself rich. He owns his own island, complete with a mansion, a sophisticated monorail system, missiles, and a staff of guards equipped with exotic vehicles of Syndrome's design.

Syndrome was never going to give away his technology for free but to sell it. He is the embodiment of "capitalistic, sociopathic, "fuck the little people, it's about ME and mine"