if someone messages you directly to request a sub instead of using this forum?

I received such a request and pointed that person to the requests forum. Anything else I should have done?

You did well. Personnaly I ignore the subtitles requests by PM.
If users spam you, you also can blacklist them (there's a blacklist function on their profile page)

If users spam you, you also can blacklist them

I blacklist almost right away. I put a lot of work and effort in this site.

The "request forum" is two clicks away. If someone is too lazy to search it, I intend to get rid of ppl (with blacklists) that bother me instead of using their brain.

That's sounds harsh, but I do "service for free" for many years now. My payment is respect and the slogan "A Brain Is Needed".