They couldn't be farther from the truth.
Truth is highly subjective.
These ideas are conceptualized through symbols.
Set, is perceived as 'evil' because of certain actions he takes, and for his own reasons. Just like some people fear Anubis, or Aset because they are keepers of the dead and funerary deities.
Death frightens people.
Murder frightens people.
I think Set gets a bad rap, honestly.
They correlate Set to Satan, for his adversarial position.
I could say that Jesus was the adversary of his time. He spoke against the reigning ideologies at the time. He was adversary to them.
Think about it. Until Jesus, it was common to stone an adulterer - in fact, the God of Old Testament demanded it.
But he said, those without Sin, cast the first stone. And people started self-reflecting, vs. judging others - being their judge and executioners.
If Jesus was the embodiment of God, in the flesh - was he opposing himself? What does Jesus represent to the people at the time, as a symbol?
Compassion
Wisdom
Common Sense
Humanity
Jesus is a very 'eastern' symbol, representative of enlightenment.
God says this, and Jesus says that.
Who do the people follow?
OT is thrown out and enter NT, this NT is in complete opposition of the OT on many points. Making it an adversarial text, to many of the laws set fourth by God.
Sacrifice is thrown out.
Murdering your fellow sinner is thrown out.
you get the idea...
As far as Set is concerned, the western world can't possibly fully grasp the intended symbolism of an eastern society, let alone ancient context.
We speculate.
We interpret.
We don't 'know', we 'think'.
Set of pre-dynasty Egypt is gravely misunderstood.
He was a sun God, and the hero of Ra.
There were developments (3000 years worth) of the Egyptian language, and lots gets lost in translation.
He was known as the pillar of stability, and later 'chaos'. The complete opposite of stability.
He was known as his 'majesty' the only God, aside Ra to have that title, at that time.
He was 'great strength, another attribute only attributed to Ra at that time.
He was Ra's right hand man, his strength and defender.
He's not demonized until much, much later. It was a common practice to demonize old gods, to make way for new ones. They lose popularity among worshippers if they have 'evil' attributes.
Today, the mythology embraced is a reconstruction of old legends.
When people engage in debates about what Set represents, I think it's important to state whether its pre-dynasty or post-dynasty periods.
Post-dynasty, Roman Isis is wed to her brother Osiris. Osiris now takes center stage, replacing the veneration for Set and Ra. Set must be demonized to elevate Osiris and Isis above any other popular Egytian Deities at the time. What better way to do that? Than to have him kill and dismember his own brother Osiris, and put Isis through torment.
Isis, is nothing at all like the Egyptian Aset. She is Romanized, to take on a 'mother' demeanor. Her original Asetian identity, she was a blood goddess, queen of vampiric peoples, and required blood sacrifice, and wasn't at all the 'mother' she is portrayed to be. She was keeper of the dead yes, but she wasn't placing lillies on their tombs, that's for sure.
Osiris, is the Roman/Greek Asar (Wesir). Again, the persona changes. The Greco-Roman symbolism make him wise, and a King that brings prosperity to Egypt. Pre-Greco/Roman reconstruction, he was a wimpy leader 'trying' to gain fame. He would often perpetuate ideas about himself to oracles, and in scriptures.
Imagine this, so Set is the big guy in charge, next to Ra. His younger brother marries Aset, and is trying to elevate himself above both Set and Ra. As Ra's defender, Set goes to smack the dog shit out of him, and a fight ensues. Set is the pillar of strength and dominance so naturally he tears his brother apart.
Aset, the master manipulator that she is. Spreads word to her worshippers that Set has done Egypt a great disservice and has become riddled with jealousy and evil. Bam! Now Set is the bad guy.
the end.