I have finally, after four years, realized how to get the SWBF2 Remote manager and Server Manger for PS2 to work on my Macbook. I haven't been trying for that long, because I sort of gave up once I heard it was an .exe file, which only work on Windows. I also stopped trying because out of each new player I met, none of them had a Mac or knew how to solve the problem.
Anyways, on to the solution...
I found this application called Crossover Games, which allows many Windows only games to run on Mac. I figured that if those games were also .exe files, then this would have a chance to work too. And sure enough I downloaded what I needed and I was able to put up a server last night. If anyone wants help trying to run a server from their Mac (although after talking to everyone I don't think any of you have a Mac anyway) feel free to reply to this topic or send me a message, and I'll go into more detail about what to do.
If only I knew about this four years ago. I can't even count the number of times where someone couldn't have a clan battle or scrimmage because no one was online that had remote access to a paid server.
Also, I need to give a shoutout to {STR}Snowfox. She is the only other player I have met with a Mac, and I believe she is the first one to actually get this working properly. She suggested to me that I should use a program called Wine in order to get it to work, and although Wine didn't work on my computer to run a server, that idea eventually led to me finding out about Crossover Games, which did work. So thank you.