Is a reprobate evil ? Are satanist evil ?
I believe you may be conflating two different things. Here's why:
The word "evil" implies that the person continually does evil. A good example from Scripture is Sodom & Gomorrah.
Genesis 6:. 3 And the Lord said, My spirit shall not always strive with man, for that he also is flesh: yet his days shall be an hundred and twenty years. 4 There were giants in the earth in those days; and also after that, when the sons of God came in unto the daughters of men, and they bare children to them, the same became mighty men which were of old, men of renown. 5 And God saw that the wickedness of man was great in the earth, and that every imagination of the thoughts of his heart was only evil continually. 6 And it repented the Lord that he had made man on the earth, and it grieved him at his heart.
Therefore to say that liberals are evil does not come close to the ad hominem of calling liberals evil. When doing that, you are making a theological evaluation on a person created uniquely in the image of God, solely based upon your (generic usage) personal dislike of his political beliefs. From a Scriptural viewpoint, that is not permitted, and I can say that because by definition, sin is an affront against God.
Again, by definition, a Satanist has rejected the free gift of salvation only through Jesus Christ. Therefore IMO, the person is reprobate
Jamison Fawcett & Brown say this about that passage:
Genesis 6:5:
Verse 5. The wickedness of man was great] What an awful character does God give of the inhabitants of the antediluvian world!
1. They were flesh, (Ge 6:3,) wholly sensual, the desires of the mind overwhelmed and lost in the desires of the flesh,
their souls no longer discerning their high destiny, but ever minding earthly things, so that they were sensualized, brutalized,
and become flesh; incarnated so as not to retain God in their knowledge, and they lived, seeking their portion in this life.
2. They were in a state of wickedness. All was corrupt within, and all unrighteous without; neither the science nor practice of
religion existed. Piety was gone, and every form of sound words had disappeared.
3. This wickedness was great rabbah, "was multiplied;" it was continually increasing and multiplying increase by increase, so that the whole earth was corrupt before God, and was filled with violence, (Ge 6:11

profligacy among the lower, and cruelty and oppression among the higher classes, being only predominant.
4. All the imaginations of their thoughts were evil-the very first embryo of every idea, the figment of every thought, the very materials out of which perception, conception, and ideas were formed, were all evil; the fountain which produced them, with every thought, purpose, wish, desire, and motive, was incurably poisoned.
5. All these were evil without any mixture of good-the Spirit of God which strove with them was continually resisted, so that evil had its sovereign
sway.
6. They were evil continually-there was no interval of good, no moment allowed for serious reflection, no holy purpose, no righteous act. What a finished picture of a fallen soul! Such a picture as God alone, who searches the heart and tries the spirit, could possibly give.
7. To complete the whole, God represents himself as repenting because he had made them, and as grieved at the heart because of their iniquities! Had not these been voluntary transgressions, crimes which they might have avoided, had they not grieved and quenched the Spirit of God, could he speak of them in the manner he does here?
8. So incensed is the most holy and the most merciful God, that he is determined to destroy the work of his hands: And the Lord said, I will
destroy man whom I have created; Ge 6:7. How great must the evil have been, and how provoking the transgressions, which obliged the
most compassionate God, for the vindication of his own glory, to form this awful purpose! Fools make a mock at sin, but none except
fools.
Reprobate mind:
The phrase “reprobate mind” is found in
Romans 1:28 in reference to those whom God has rejected as godless and wicked. They “suppress the truth by their wickedness,” and it is upon these people that the wrath of God rests (
Romans 1:18). The Greek word translated “reprobate” in the New Testament is
adokimos, which means literally “unapproved, that is, rejected; by implication, worthless (literally or morally).”
Paul describes two men named Jannes and Jambres as those who “resist the truth: men of corrupt minds, reprobate concerning the faith" (
2 Timothy 3:8). Here the reprobation is regarding the resistance to the truth because of corrupt minds. In Titus, Paul also refers to those whose works are reprobate: “They profess that they know God; but in works they deny him, being abominable, and disobedient, and unto every good work reprobate” (
Titus 1:16). Therefore, the reprobate mind is one that is corrupt and worthless.
As we can see in the verses above, people who are classified as having a reprobate mind have some knowledge of God and perhaps know of His commandments. However, they live impure lives and have very little desire to please God. Those who have reprobate minds live corrupt and selfish lives. Sin is justified and acceptable to them. The reprobates are those whom God has rejected and has left to their own devices.
from
https://www.gotquestions.org/reprobate-mind.html
Can you now see the differences?