It's important for this type of IEOS that the team and initial investors have vesting. That way they cannot sell their coins for at least a year or 2 years. That way the next investors are protected from big whales that just want to pump and dump and gives the project enough time to develop and grow.
I think whales participated in IEOs. With millions of dollars in sales achieved in just a few minutes or hours, I think most of the buyers are whales and I think this is only natural because everyone wants to make a profit. The prices of almost all tokens and coins are currently down and not limited to IEO tokens, so I don't think we need to worry as long as the project is still running and has active transactions on the market