This is a great idea, but...
Sometimes this filter will work very well for a few days, then for no reason I can see, starts to block every feed post completely. So nothing from feeds gets posted at all once this happens. No changes are being made to the filters.
If I delete all the filters, then re-enter them, it will usually work well again for a few more days. Then it blocks everything again.
I haven't measured the exact time it starts to block all feeds, but it seems to be inconsistent, seems like after about 3 to 5 days. Sometimes it will block everything very soon after I re-enter filters, within 2-3 hours but this is not often.
For a while I kept deleting and re-entering filters, and I get optimistic every time it does work. But this time I'm going to deactivate it I'm afraid. It just won't keep working.
It is a great idea though.