Calling Ethereum a scam is far fetched, the delays are real, but it being a scam is just crazy.
It is a scam because it never delivered on any of its promises.
Ethereum was supposed to be decentralized, but it wasn't.
It was supposed to be secure, but it wasn't. The DAO mess and lots of other vulnerabilities that were never fixed.
It was supposed to be fast and cheap, but it wasn't. Vitalik was advertising it as "fee will never rise" but we all know how that ended up.
It was supposed to have an immutable blockchain but it didn't. The roll back killed it.
and so on...
When they advertise something but sell you something else, that is the definition of a scam.