“But just as he who called you is holy, so be holy in all you do; for it is written: “Be holy, because I am holy.”” - 1 Peter 1:15-16
Sometimes, to win a debate after having lost it, one accuses the winner of being “Holier than thou.” The implied holiness is not the same as what Peter is referring to in his letter.
Some say Peter could not have written his letter because they don’t believe in adult learning. After Peter’s education as a disciple of Jesus, Peter was privileged and had ample opportunity to learn advanced rhetoric. But the wording here is simple and pure. God is holy. God is exalted and above the sin of which people are immersed. In order to deal with sin, it is important not to deal in sin, but to look for God. The simplicity of the words is what informs those who claim Peter could not have written it.
But, in not dealing with the trade of sin, a cheap shot is to say that the winner is unaware of the world in which they have stood in judgement. A populist argument at best, which can win from populism.