Probably true for most.
For us, we actually rely on an old email solution that doesn’t use STARTTLS for outgoing emails from internal systems (that is handled later in the chain) and since the documentation said `DISCOURSE_SMTP_ENABLE_START_TLS` is optional, but default true we sat this to false intentionally.
I can Dismiss this advise, but it just shows up again and other admins will wonder if there is something wrong with out setup (there isn’t; test mail works fine!). Is the advise intended to be so persistent?