To be honest, lots of coins have been dumped by me as well... and why? Because they were just pump coins and stupid coins back in 2017, but since then they have just fallen in value, simply because they were junk coins! But, those that I keep close to my heart, they I have kept throughout the bear market and I really enjoying seeing them back on the rise now!
It is easy to feel regret about selling airdropped coins, but there will always be regrets in markets such as this one. Forget about it, have fun, take profit, and be happy whenever you are able to take profit :)