Because it is man’s reasoning and it is not scriptural and unsupported by scripture. You cannot be justified until after you’re saved period. Unlike calvanist I actually believe scripture. When the jailer asked Paul what must he do to be saved Paul responded by telling the jailer he must believe on the Lord Jesus. Paul never mentioned election to the jailer. Revelation 22:17 says whosoever will take the water of life freely. Peter explained election not that any calvinist understands it.
1Pe 1:2 - Elect according to the-foreknowledge of God the Father,through sanctification of the Spirit, unto obedience and sprinkling of the blood-of Jesus Christ: Grace unto you, and peace, be multiplied. Elect according to what ? Answer the foreknowledge of God.