Once the airdrop is over the price is going to crash heavily. Onion is just a cheap copy of Tor coin which wasn't legit.
People who participate in airdrop are not fools. You do not have deeponion. Why worry about it?
Question is : why don't you worry about it ?
Here is the answer, you have sell most of them : (and you took the right decision)
Total Sent (ONION) Total Received (ONION) Balance (ONION)
563,810.76662691 629,065.34027882 65,254.57365191
Some are smart, as you did, but many will loose everything.
If he "sold" that many onions, then he bought alot to begin with. You don't receive 500k onions from the airdrop