I don't understand the rationale for removing support for any algorithm. I can understand disabling support, but why remove it? I have often needed to connect to ancient systems that only support very old algorithms. From a modern ssh client, I will usually need to specify the needed algorithm on the ssh command line in order to connect.
E.g.
ssh -oKexAlgorithms=+diffie-hellman-group1-sha1 [email protected]