We don't believe in any "assured salvation," if by that you are arguing for an antinomian system. ("I can commit any sin I want to and go to heaven without repenting; I'm infallibly saved.")
Most "assured salvation" Protestants aren't antinomians, however. They say that someone who seems saved and then sins grievously and dies without repentance was never saved to begin with. That seems like a dodge to me; did they know they were never really saved at the time they were telling people that they were infallibly saved? If they did, then any "assurance" you think you have is sitting on sand, because they thought they had the same assurance.
In the end, it's really quite simple. "He who confesses me before men, I will confess before my heavenly Father. He who denies me before men, I will deny before my heavenly Father." (Mt 10:32-33) "Not everyone who says to Me, "Lord, Lord,' shall enter the kingdom of heaven, but he who does the will of My Father in heaven." (Mt 7:21)
Make sure your actions (not just your words) confess Christ and do not deny him before men.
It is very odd how some Catholics seem to resent my saying, "I am saved through the blood of Jesus Christ, Who Was and Is, and Is to come."
Should you not feel joy instead of anger?
Be very very careful when "warning" others about their salvation or lack thereof, especially when you yourselves claim no assurance.