Need to do that to get anything to work!
In my case, upgrading a project that was initially begun with an earlier version ended up with both ionic-framework and ionic-angular under node_modules, which resulted in the CSS being built from older source that did not include the necessary stuff for the spinner. I had your exact same giant black circle, which is how I found this topic. It was only after I manually nuked ionic-framework out of node_modules, that I was alerted to stale references in ionic.config.js. After changing those, the CSS files contain the spinner rules and the spinner behaves as expected.