For me at least, I have a very young audience, and everyone wants to be on Discord. If a nice community member proposes to moderate, it's basically almost no effort.
To put it short: I experienced Discord as all pull from the community, it wasn't even my idea to start it. Other platform you push and nobody wants it. Don't ask me why it works, it just does.
Survivorship bias? You're counting all the people who want to use discord as support for using discord, but since you[1] have no other avenues for the non-discord people you don't know how many users you've lost simply because you've silenced them.
IOW, you're[2] looking at the 5 people who express support for discord but ignoring the 500 who hate it enough to not use your support at all.
I think, if you're a business using discord for user support, you should should be wondering, if you've got 100k users, why are only 1k people in your discord?
[1] Not you personally; for all I know you have multiple channels, which include discord. The places who normally use discord only have one channel for users to use.
[2] Once again, not you personally.
I'm 44, so for me a forum is ideal, Discord is way too intensive.
Then one of my members started a discord years ago and a lot of members went there. I switched everyone to an official one, and one member volunteered to moderate.
I would say most questions come from Discord, then YouTube comments, then email. My own forum wasn't as popular so I closed it due to lots of spam that I had to manage.
I also pushed hard for Reddit but never took off (I liked reddit more)
One thing to mention that is probably important: this is in gaming sphere with lots of kids, teenagers and young adults. Also used in schools by teachers.
Obviously, it works for you. And it works for people who are already dedicated Discord users. But unless that's 100% of your TAM, then not only are you going to be missing people, but you will have a hard time even noticing, because others will self-select out and you'll be left with a thriving community that feels good to you.
So at the very least I'd be doing user interviews across the TAM. It's legitimate to say, "Our initial target audience is only people who are already happy Discord users." But that should be on purpose, and you should have a plan to move toward the broader audience and that will include addressing concerns like in the article.
Are they discussing this on twitter or reddit? Are they making YouTube videos? Did one of them start a Discord with lots of people there? Once you see what works, make an official one.
Funnily enough Discord was the only one I didn't start myself. I liked something async with proper Google searching better.
So even when I tried, I wasn't able to steer them.