Actually, I believe it's the contrary.
With email you have to obtain a valid TLS certificate, set up SPF, DKIM, and keep eye on the DNSRBLs so you're in good standing. And if Big Company's mail service suddenly decides they don't like you, it won't help. Oh, and spamassasin/rspamd/milter/greylisting/etc stuff so your email server doesn't get thousands of emails per day few weeks after some bot detects your host is listening on tcp/25.
XMPP has less adoption, spam exists but is much rare, so there's less stuff to do. Install a package, get a TLS cert, publish an SRV record (IIRC that's not even strictly required), and that's it. A bit fewer steps.
Not to say email is MTA+MDA combo (+some fancier LDA, +Sieve if you want more that a simple system) while XMPP is a single piece of software (unless you want transports or external extra services).
That's what I thought as well. Please link tutorial on this.
I'd agree with /u/problems suggestion to try Prosody. http://prosody.im/doc/install + http://prosody.im/doc/configure + http://prosody.im/doc/dns#srv_records + http://prosody.im/doc/certificates are probably all you have to do to get it up and running.
XMPP SRV record documentation can be found here, if you need to use it:
https://wiki.xmpp.org/web/SRV_Records
If you're finding the documentation to be insufficient, let me know, I might write something more detailed up.
I'd love to see an up-to-date tutorial that opposes my statement, eg. setting up prosody (or something lightweight) on debian (or similar) with multiple domains for multiple accounts, sending and receiving test messages from another XMPP hub, so if you know one, please link it.