As you noted, the GPL permits people to make whatever technical
changes they want. So I cannot "disallow" the use of ssh from
Emacs--or any feature. (That is one of the good things about free
software, that the developer does not decide which features to allow.)
The choice that I *can* make is how much to actively support any given
idea.
There are more than two alternatives for how much to support this
idea, and I haven't yet decided what I will do. I only know one thing
I will not do--I won't prominently advertise in the Emacs distribution
the possibility of using ssh.
I might install some code in Emacs that works with ssh, or code that
can be used for that purpose by setting some variable to "ftpsshd", if
you know about the existence of ftpsshd.
I don't think the
XEmacs project will follow your line of reasoning -- usefulness to the
users comes first, politics comes second.
This is one of the ways that the rivalry between Emacs and XEmacs is
detrimental to the Free Software Movement. It is a popularity
contest, which makes it hard to say no to anyone. Doing whatever the
typical users want tends to reinforce the majority view, not to change
it.