Re: Why do you participant in Airdrops?

I don't understand, too, why there are so many participating airdrops appearing on this forum.

Is it still shocking on why most of the announcements were published here? this is the largest bitcoin/crypto forum so that's why every project aims to have their announcement threads published here.
It's easier for them to reach their community out if they are into a huge and published community like bitcointalk. That's why they have a dedicated and specific section for that kind of announcement which is the bounties.

There are too many people has been earnings in airdrop free tokens since its free nothing to lose here so more people are grabbing the oppotunity to earn from free.

and some also has already get profit from airdrop before so they continue doing it.

Yes, there's nothing to lose with those airdrops. They were for free since then but if you were aware of the complaints of most bounty hunters. Those tokens don't have any value, they were lucky to have a few token and if ever it will hit the exchange which will have its value.
Your efforts will be wasted if you are still into it. Those times when airdroppers have earned with it were gone.