My question is, are these projects legit or is it just a plan to grab the investors' money on this DeFi hype?
You should look at each project seperatelly. If someone name them defi that does not mean anything about being legit.
This should be the right answer to the question of OP, projects are rated individually.
You can't say that altcoins proejcts are scam when not all the projects are scam, and you can say bitcoin a scam when it's only use for scamming people.
Understanding of this matter is very crucial as that would give fair judgement on the market in general.
DeFi Proejects.. as you can read on the words, it's projects, some could be legit and some may not.