What is the point of digital signatures if confidentiality is violated? Lets say we use RSA as the signature method.

Alice wants to send a message to Bob and uses RSA signing. For that she signs her message with her private key. But everybody could now have access to her message if one just decrypts the signature with Alice's public key.

What is the point of digital signatures if confidentiality is violated?
Digital signatures are not designed for confidentiality. For the simplest counterexample to the implicit conclusion that there is no point to digital signatures without confidentiality, consider the use of PGP signatures. People may sign a message that they send to a public mailing list, allowing others to verify that they indeed said that and not an imposter pretending to be them.
Also, you seem to be misunderstanding how digital signatures work. It is not encryption that you decrypt to verify. A digital signature is a mathematical operation on a hash of the message that you verify is valid for the message. You don't recover the message itself from the signature.