@iasenko, @Thirdspace, I didn't knew that. I thought that number of airdropped Merits was determined by user rank and his activity, no matter he was active in 2017 or no. Seems that I was wrong. Well, good to learn something new, thanks guys!
You are right it all depends on the activity earned by the user but it will depend on how much the activity the user earned during that year (2017) so it still depends on the user being active or not. You can read it in the
original announcement thread in the meta section that theymos created about the merits system.
Trivia:
For current members, your initial merit score is equal to the minimum required to your rank. Of that, a certain amount (less than the usual half) is spendable. The spendable amount was calculated based on your current rank and the number of activity points you earned in the last year. A Legendary member who hasn't posted in the last year would still be Legendary, but would not have any spendable merit.
So not all people even if they have the same ranks or activity have received the same sMerits to give after the announcement.