I always check out the writing of new people who comment on my stories. To see if I like their writing and may want to follow them. I figure, if they took the time to comment on my story, it is worth the time to check out their stories.
I sometimes check out those who just clap. So that strategy is somewhat effective, in that it got me to look. But if they are following 12k people that is a good indicator that they were just fishing. And I don’t need to bother.
You are correct, it is hard to keep up as your follow number increases. And you have to be picky if you don’t want your feed full of stories you aren’t interested in. Of course, I have my favorites on Medium, but I do like to find new writers I enjoy also. I guess it’s a good problem to have.