I got accepted into a top 10 school for CS (Computer Science) but I was rejected by a professor with whom I wanted to work with. No feedback after resume submission, just "I found another student." If I can't find a professor that wants to work with me in something I'm interested in at a MS level, should I even attend? Or should I just try to write my own paper (sole author) and see what happens? I want the research experience for PhD applications in the future.
If you can get a TA or otherwise afford to go, you might still consider it. You are likely to take around six classes your first year. You might meet several professors that you want to work with and who want to work with you. Plenty of students come to grad school without an advisor lined up and manage to find one during their first year.
It's unlikely but not impossible that you will work by yourself to complete a publishable paper in CS. Even if your work is purely theoretical, you are likely to need guidance at the very least and other resources in general.