That excuses lying about your faith?
What an utterly heartless thing to say.
The people in question were put in a situation where living as Jews was almost impossible, so they underwent false conversions in order to stay alive but continued to observe the Torah in secret. They lied to stay alive, not in order to conduct some vast evil conspiracy to convert Spain to Judaism. Shame on you for parroting this nonsense.
Do you think any of those Marranos would have converted if they had been left totally in peace to practice their religion? Any who would have done so would not have been good Jews, and any who would have continued to practice both religions at once would simply have been very sick, confused people.