1. Yes I guess that the “Bulk Delete Plugin” page loaded fully.
2. No, I didn’t any errors, I got only “Deleted 0 posts from the selected categories” message.
3. I am sorry, I didn’t wait for that long to check if it’s something with the cache.
But I made it in the following way,
I renamed “uncategorized” as “Admin Talks”. Then I created another category “test” and set it as default & came back to the “Admin Talks” and deleted the whole category. All 3000+ junks are gone! ??