Yeah that feature is mostly to help people who have followed hundreds of inactive profiles. There will be false positives, but I save them in a list to mitigate that. The "graveyard" list is useful besides with false positives because it lets you see if anyone came back from the grave.

I'll try to work on improving the situation with false positives by not relying on a hard coded list of relays. I can also add a button or checkbox next to individual profiles to selectively unfollow and simultaneously add to the graveyard list.

It's great to hear feedback, and I'm glad to hear people are using this tool!