That kind of "sweetness and light" is, in reality, nothing but bitterness and darkness. Bitterness, because it expects non-Catholics to swallow whatever the current magesterium thinks is the truth - regardless if there is Apostolic or Scriptural evidence or basis. And darkness, because, at the core, is an accursed gospel that denies grace and the role of faith in Christ's substitutionary sacrifice for our sins. Accepting this false gospel - that our works are necessary to our salvation - will lead to eternal darkness separated from God. Though Roman Catholicism is certainly not wrong about everything in the Christian faith, this one perversion of the gospel is serious enough that it can deceive a person into trusting in themselves instead of Jesus Christ for salvation.
Therefore, since through Gods mercy we have this ministry, we do not lose heart. Rather, we have renounced secret and shameful ways; we do not use deception, nor do we distort the word of God. On the contrary, by setting forth the truth plainly we commend ourselves to everyones conscience in the sight of God. And even if our gospel is veiled, it is veiled to those who are perishing. The god of this age has blinded the minds of unbelievers, so that they cannot see the light of the gospel that displays the glory of Christ, who is the image of God. For what we preach is not ourselves, but Jesus Christ as Lord, and ourselves as your servants for Jesus sake. For God, who said, Let light shine out of darkness, made his light shine in our hearts to give us the light of the knowledge of Gods glory displayed in the face of Christ. (2 Corinthians 4:1-6)