There's nothing ironic about it. Irony is only when the result is something that is not expected occurs that is contrary in relation to what would be expected. Easter has no expected correlation to a number that may or may not have to do anything with carcinogens.
The irony being "Let's secretly celebrate harmful (and likely illegal) substances that most would warn us about" during a religious holiday. Perhaps is more coincidence than ironic, but I appreciate the english lesson, MMX.
