The Reformation returned Christianity to the Bible, and away from the errant doctrines of corrupt men who for centuries had slaughtered anyone who challenged the papacy's imperial bombast.
Rome's sins are legion -- kneeling to a priestcraft made up of deluded "alter Christus;" elevating a simple Jewish girl to "co-redeemer;" praying to dead people as "mediators" when there is only "one mediator between God and men, the man, Christ Jesus;" concocting cruel lies like purgatory which declares that Christ's justification of His sheep was incomplete and lacking, so men have to work to finish Christ's atonement of them; teaching a false baptismal regeneration; believing in a works-based salvation; bowing to a fallen old man in Rome as "the infallible head of the church" when Scripture tells us no man but Christ was infallible and that Christ alone is head of His church on earth.
Dot.
Dot.
Dot.
Semper Reformada.
Actually, the Bible itself shows sola scriptura to be false.
"Many other signs also did Jesus in the sight of His disciples, which are not written in this book. But these are written, that you may believe that Jesus is The Christ, The Son of God: and that believing, you may have life in His Name" John 20:30-31.
"But there are also many other things which Jesus did; which, if they were written every one, the world itself, I think, would not be able to contain the books that should be written" John 21:25.
"Therefore, brethren, stand fast; and hold the traditions which you have learned, whether by word, or by our epistle." 2 Thessalonians 2:14.
"believing in a works-based salvation..."
"Then shall The King say to those on His right hand, Come ye, the blessed of My Father, inherit the reign that hath been prepared for you from the foundation of the world; for I did hunger, and ye gave Me to eat; I did thirst, and ye gave Me to drink; I was a stranger, and ye received Me; naked, and ye put around Me; I was infirm, and ye looked after Me; in prison I was, and ye came unto Me." Matthew 25:34-36
"For, the Son of Man is about to come in the glory of His Father, with His messengers, and then He will reward each, according to His work." Matthew 16:27
"And if I should have prophecy and should know all mysteries, and all knowledge, and if I should have all faith, so that I could remove mountains, and have not charity, I am nothing." 1 Corinthians 13:2 (St Paul).
"kneeling to a priestcraft made up of deluded "alter Christus"
And He took bread, gave thanks and broke it, and gave it to them, saying, “This is My body given for you; do this in remembrance of Me.” In the same way, after the supper He took the cup, saying, “This cup is the new covenant in My blood, which is poured out for you." (Luke 22 19-21)
Many, many people were killed by protestant rulers and brigands. There is little sense in even attempting to attribute 'slaughter' to none but the Catholic empires.