Tilikum should be deseased

A while ago, Harambe was killed because a young child fell into his enclosure with no sustained injury.

However, after three malicious murders, an orca named Tilikum is still alive. Even though they need his sperm, the whale has no sole purpose of being alive. He is a danger to anyone and because of this, he is also too dangerous to return from being in captivity.
I think that Sea world are being petulant about the situation and need to put him down before it's too late. Even though no trainers can go near him, veterinarians still risk their life to treat him.
Consequently , I believe that it is unjustified that a gorilla with no caused death was killed after and incident but a whale with three acknowledged murders is still Alive. I love animals. However, a dangerous orca who is alive is sickening. Sea world need to stop mollycoddling him and act as civilised adults and put him down for the safety for staff and visitors.