I get your point, but at the same time a lot of the alien cultures we only see from a very narrow view. If you dropped down in the middle of West Virginia, you'd have a very different idea of what Americans are like than if you dropped down in urban New York.
Klingons have scientists and doctors. They're considered a lower rung of Klingon society though.
Aliens in Star Trek are largely used as a mirror of humanity in order to show the audience where we might end up if we aren't emotionally balanced. They're vehicles for storytelling. In Enterprise Shran remarks how humans are unlike any specie they've encountered in that they are always in conflict, valuing logic and reason while willing to engage in violence.
There's just something strange about the fact that the episode implies Klingons are biologically and genetically predisposed to anger and violence. Like a human B'Elanna is incapable of being angry because all her "angry genes" are Klingon.
Think about how scientists used to measure human skulls to "prove" that white people were superior to black people because they had bigger shaped heads or whatever... it just sort of hearkens back to that kind of thinking, which is a bit strange to see in Star Trek.
The Ferengi are the worst stereotype in all of Star Trek. DS9 did somewhat temper this later, but those TNG episodes, man. Just indefensible.
Oh yeah, the Roddenberry Ferengi were terrible. Although I'm sure I've heard a comedian make the joke that "if you think the Ferengi are racist, maybe YOU are the racist." lol
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I'm almost done Voyager S2, skipping some of the Kazon episodes from time to time, and I don't hate it as much as I thought I would. You have the genesis of some ideas here, like Janeway having sex with British men on the holodeck and from time to time they pretend that they are out of supplies, but the fundamental problem is still the fact that it might as well have been a ship in the Alpha quadrant.
It's interesting because they wrote in an "out" with the female Caretaker so that they could use her to send the ship back home if they ever needed to (of course that, like most of the S1-2 storyl ines, are completely jettisoned). But once they rebooted it with all the Borg porn, I guess they didn't need to worry about that anymore.
At the tail end of S2 they try to do a "DS9" style arc with Paris turning into a slob and getting into a fight with Chakotay so that they could expose the Kazon spy on the ship, so there's an attempt to try to tell some kind of serialized story. But this is peppered in between random episodes where Tom Paris turns into a space lizard or the Doctor falls in love with a patient (which is a thing that happens to every single Star Trek doctor, it seems... you'd think they'd teach a course on ethics at the Academy).
Also, I'm starting to remember that every Chakotay episode is some vague "he's Native American" story (CHAHMOOSEE) and that every Kim episode is him being abducted by sexy aliens and then running away from them to rejoin his ship.
