> Why would I want the data to be decrypted at each point and why would datacenters do that?

I think they mean the data must have existed in plain text before it was encrypted, and will exist in plain text after it is decrypted.

At some point “your” server in a datacenter somewhere needs to decrypt the data to do something useful with it, after all you’re paying for compute, and homeomorphic encryption is too slow, so the work is done in unencrypted data.

There it is. Your data in plain text in RAM.

TLS will protect your data in transit, but it can’t protect you against a compromised recipient.