Company's been evil since the 70s. Though Dan O'Bannon referred to Ash's character as the Russian Spy so there was a Cold War motif in the first Alien, from his point of view (he didn't approve of the idea of Ash, even though he thought Ian Holm killed it in the role). The yuppie 80s thing was more Paul Riser's character from Aliens.
I didn't see the company as strictly evil in Alien, though, now that I think about it. Ash was crazy enough but the company itself seemed indifferent. Things are rough for its employees, for sure, but it's not literally standing over them with a whip, either. More often than not, the employees do more harm to themselves once the Alien is lose than the company does.
But I tend to categorize evil as "direct, sadistic or cruel, voluntary action." This seems apropos for the Alien, but according to Ash, it is unclouded by "delusions of morality." It's just a killing machine. If the alien really is just a weapon, then it is neither good nor evil. I saw a horror film called The Guest where the character was programmed to be the perfect soldier. Once his directives crossed over into "kill territory" he couldn't stop himself. There was no choice involved. Neither was the Alien really choosing to do what it did.
The company probably had a choice, but there's such a huge disconnect. It isn't really one person, and the choices made by whatever committee dictated Ash's special order probably had never met Dallas or his crew. And they were all contracted, so who knows where they all came from before the Company picked them up. To the Company, Dallas and the other crew members of the Nostromo were just, as Dillan told Dutch, "expendable assets." Does that make the Company evil? How can it strictly be evil if the people it's harming it never sees?