This is mere child's play!
(don't mind stuff not loading on my images)
This is my dashboard
Wait a moment though! You may see this "magnifying glass" looking thing at the top, left from the profile picture!
Click on it and this happens:
(do note that this is on most pages of the website, and that the search bar for the forums is separate from the main website)
So we jot down a name, maybe not the most useful results. Where is the moeslasher we want?
Click "SHOW MORE" and you will be transported to a page containing this:
now, you see that our user (that we searched for) appeared at the top! We don't have to stop here! See how below moeslasher there is a bunch of manga? Well we can filter the results!
Click on "Everything" and you get a drop down menu like so
Below, you can see that I have used this menu to show only the Manga results of the Fullmetal Alchemist query. (although there are unrelated manga below the first three)
Just use what I did and switch Manga with Users and you should be able to find people using this feature.
This is also a link to the search page if you don't feel like clicking the magnifying glass and 'show more' to get there:
If you just want to find random users instead of specific users. You could follow people who are on the forums and then follow the people they chat to on their feed or whatever.