That's like saying that researching forbidden occult lore in Call of Cthulhu isn't dark, evil, and won't drive you criminally insane (hint: it does). Warlocks are also constantly characterized by a thirst for power. A look at the spell list shows exactly what kind of power they get - offensive damage spells, mental manipulation, curses, and darkness.
While that's not evil, as D&D defines it, it is definitely on the darker side of magic.
Blade pact relies on Hex and their 12 ability to deal necrotic damage. Tome is generalized, literally; it lets you get spells from anywhere. Chain has two fiends and two fey-like familiars. The fiends are definitely evil. So, being right once out of three isn't bad.
So, let me get this straight. Dominating and controlling people like the illithid do isn't evil? An ability designed to make you think you're insane or cast into another plane called "Dark Delirium" isn't dark? Granting spells that revolve around insanity and mind control isn't?
Eldritch blast is often accompanied by Hex, which is absolutely necrotic. Arms of Hadar is evoking beings beyond reality into this world, generally the same sort like the evil aboliths. Armor of Agathys calls upon a fiend.
Only if you ignore the spell list, which is dominated by necrotic damage, curses, excessive mind control, deception and inflicting madness, calling upon creatures of darkness, draining life energy, summoning undead, inflicting fear, and shadows/darkness in general.
Never mind that the class as a whole tends to name things in a negative light. "Agonizing Blast," "Hurl through Hell," "Dark Delirium," "Thrall," "Bewitching Whispers," "Fiendish Vigor," "Dreadful Word." The list goes on. The sheer weight of everything makes its clear that, even if we're not talking about being Evil here, its definitely on the dark side.
Yes, you can rename and reflavor everything at individual tables, but I prefer to discuss just the default class, and there are any number of things in the class that are troubling to a Good being.
And that's a large part of the attraction of the class. That whole dark, troubling edge to them, struggling to do one thing, while temptations to do others are abound.