If they mandated discord as a closed support community sure, but you can't be too upset by the mere affiliation with a discord channel when they also offer all the above
If I remember correctly, their matrix channel was flooding with spam and abuse which was primarily coming from Calyx, which by the way is an terrible OS. Even a stock OS would perform marginally better in terms of security than CalyxOS
This was not a project I expected to use Discord for support. Sad.