Reading this, it seems to imply that key exchange in TLS is an insecure process. This is not the case. Several (secure) key exchange mechanisms may be used, such as http://en.wikipedia.org/wiki/Diffie%E2%80%93Hellman_key_exch...
The key exchange in itself is an insecure process that may be attacked with a man in the middle attack. However, this is a known limitation of the key exchange protocol which is fixed by adding a public key signature to the key exchange messages so TLS is not vulnerable overall. </oversimplification>