Where was this clarification made?
That doesn’t make any sense, since there’s a clarification stating that the returning player free deck is limited to 1.
Here you go:
https://us.forums.blizzard.com/en/hearthstone/t/a-few-notes-on-the-returning-player-experience/27240
Only people who didn’t log in for that specified period qualify. Even if you stopped logging in for four months starting today, you won’t qualify. The dates are very specific.