Not anymore than it should be called ICQ. The XMPP protocol does not share any of the privacy-oriented roots of signal.

A little tongue in cheek, of course. I suppose you could run an encrypted protocol over any untrusted transport.

The point is that Signal is designed around your real life identity. That's a real use case, it helps discoverability immensely, and that's generally why people use it. Should you wish to communicate pseudonymously there are plenty of options already available.

(The XMPP suggestion was only partly in jest. Any modern client, such as Conversations, is pretty solid. But there is no shortage of options for chat.)

...

X stands for extendable in XMPP. Read about OMEMO.