When resetting List’s permissions anonymous access to the catalog is removed as well.
When you publish a List as catalog for use on your public-facing website you will in most cases enable anonymous access to the catalog’s content. Enabling anonymous access on a catalog will alter List’s permissions and break the permissions inheritance from the parent Web. In some scenario’s you might need to change List’s permissions to, for example, grant access to a new group of users. Depending on how big the permissions change is you might choose to reset permissions and set them to the desired values. If anonymous access on the catalog was enabled, resetting List’s permissions will disable it. As a result the catalog content will not be displayed on your public-facing website anymore. In order to restore it, you will need to re-enable anonymous access on the catalog.