We have had some customers experience slowness while using the plugin whenever they have third party browser extensions that interfere. It seems some password manager extensions are often the culprit (for example, LastPass and 1Password are both known to interfere).
Are you able to run the bulk editor using a different web browser as a quick test? We recommend Firefox and Chrome, however it works with all major browsers.
If the bulk editor works fine in another browser then let me know which browser causes the slowness and I can help you track down which extension is interfering.
