I don't think he is But if so I'm not

"Goood..." ahem, excuse me. Sarcasm does not work well online.

"... group of people fighting for what they believe"....

Does "fighting for what they believe" excuse them from being "genuinely evil"?

What if it is a "religion" that does horrible things to children? Does that make them evil enough?

Now, if you'll excuse me, I need to rewatch Order 66.

Does "fighting for what they believe" excuse them from being "genuinely evil"?

Agreed, there are many genuinely evil people who fight for what they believe in, the two aren’t mutually exclusive. Beliefs can be evil, such as believing that the murder of innocent people is okay- and backing those beliefs up with actions only solidifies the fact that that person is evil.

Here’s the way I look at it: Sith BECOME evil because they let the Dark Side corrupt them. I think it is unfair to call someone evil just for being a Sith, or to call someone good just for being a Jedi. Not all Jedi were good. I don’t think it’s really that black and white.

Yeah, especially now. You see former Jedi become Siths, and vice versa.

Or perhaps not so much for the Sith. I was going to say I'm thinking Asajj Ventress, who then again was a Sith apprentice in the making. Dooku's words notwithstanding. And hell, years passed since the Clone Wars, and Ahsoka doesn't see herself as a Jedi. Point being, we're kind of past the black/white era now.

We have Palpatine as a prime example of what the Sith are generally like. Selfish, anger fueled, murderous psychopaths. There’s no ifs, ands, or buts about the nature of the Sith. Even if they used to be good people prior to their conversion to the dark side, what they become is unquestionably evil.

While, as shown in material such as SWTOR, there can be Light-sided Sith, but that is akin to a Dark-side Jedi. They do not properly conform to the guidelines of their religion, and do not represent the whole of their order.

Basically individual Sith can be good, but this is rare, and as an religion/organization they are completely evil. Fighting for what you believe in does not make you good. Many Nazis, perhaps even Hitler himself, believed in what they were doing. Sith is a religion, but as Vader 5233 said, there can be evil religions.

I'm pretty sure the order with a massive emphasis on empowering the negative aspects of one's emotions and personality and encouraging things like fascism, dictatorships, genocide, killing of mentors and apprentices, and xenophobia are textbook evil.

Not "evil" in the black-and-white sense, where evil is going against good, because they prefer bad. Star Wars moves beyond that concept, but they are evil.

The Sith are individuals who found that the currents of energy that is fear, anger, hate, aggression and greed within them, are able to energize them, bring them swifter, more powerful reactions, so they can be weaponized. They developed a tradition that focused on perfecting their ability to do this, leading to developing abilities like throwing deadly bolts at people. They promote a mindset that puts the "I" in the center and treats everything and everyone else either as threats to the "I" that must be destroyed or as means of pleasing and satisfying the "I," that can be obtained through possession. Their ultimate goal is to make the "I" immortal and to achieve the ability to possess the things that bring them satisfaction and pleasure.

They are motivated by and they wield fear, anger, hate, aggression and greed.

Whether or not this satisfy your criteria for religion is your personal business, and sure, you can say that they are a group of people fighting for what they believe.

But Star Wars tells us, this is what makes someone evil.