Am I doing right adding Real Time Exclusions for Firefox?

Firefox updated to version 36 a few days ago. Since then it has been very slow to load. Once up and running it is fine, opening bookmarks quickly enough. Even when Firefox is open, if I click a link elsewhere for it to open in Firefox there is again a delay.

Looking at the help pages within Firefox (or rather the FF community support) it lists adding folders to the Norton Real Time Exclusions list - and it works as FF now opens quickly once again.

But I was a little concerned how safe this is. Could someone who knows please inform me. Attached below is a screenshot of the exclusions as recommended.

Thank you.