I think when once secure always secure is undermined, that is evil. Satan has been a liar all his life. One such lie is when he thinks to convince Christians that their eternal security in Christ, as Jesus taught, is a license to sin.
While we're told in the Bible even Satan can quote scripture, it is a blessing that the poor fool is unaware of 1st John 3.
And I call that a blessing because those of us who are aware of the passage know Satan is lying due to that passage alone. When the enemy of righteousness presumes to denounce eternal salvation, which is what Satan is doing when he presumes to say once saved always saved is a lie, and it is obvious by the mere word, "eternal", he fosters that falsehood upon those who are not familiar with the 1st John 3 passage.
But you know that Christ appeared to take away sins, and in Him there is no sin. No one who remains in Him keeps on sinning. No one who continues to sin has seen Him or known Him.
Personally, I find banning any topic in a discussion, generally speaking and not in opposition to what rules may apply here as pertains to banned subjects, is a mistake.
God given intellect is best exercised when we discuss that which we find to be contrary to what we deem is worthy of our attention. If we're opposed to a school of thought, but we know nothing of that school because we presume it is unworthy of our attention, we're not arriving at a rational conclusion. Because we've no idea what we're talking about. Rather, we're displaying our fear of learning about something we do not currently understand.
If it is false, it is best to expose that from our point of knowledge. Which can't be achieved if we refuse to engage.
The school of thought that is opposed to eternal salvation is an enemy of truth and the good news Jesus died to seal eternally with his holy blood. And it also revokes the promise.
Those opposed to the eternal security, eternal salvation, that is the Gospel should be confronted and silenced by the Gospel itself. Since it does not speak to them, they speak against it. As a Christian I find that unacceptable.
Eternal Salvation, and our faith, all irrevocable gifts of God, (Romans 11:29, John 3:16,) is not a license to sin. The Satanic teaching that it is, is precisely that. Satanic. Jesus didn't die to promote Satan's ministry. No Christian should ever stand for it to promote itself right before their face. Anywhere at all. Matthew 7:15-20.