Defi is not a scam, just that those who are not try it before look at it as a scam. it's not good to hold your coins long in Defi, because the price can drop at anytime.
You have to lock your money in pools. Can you call it as risk? Do you forget the DAO hack years ago?
Lock to get money and interests (it looks like bank savings) but crypto is volatile and if you look at the price of DeFi tokens. Their price is very high now and I am sure it will fall gradually. The lock percent does not make sense when investors feel fear of DeFi someday and when market turns bad, locked tokens can not stop price falls.