The difference between ICOs and Defi is that Defi is not 'initial'
I totally agree with you. ICOs was mainly selling wind to naive people whereas there is real technology behind Defi. As you said a lot of this Defi is still in very early stages and it is therefore quite risky. Smartcontracts is nothing else than code and if the code has weeknesses it can be quite problematic. When ETH prices dropped in april, people on Maker DAO lost everything because there was a bug somewhere.
Thanks a lot for your comment!