Even the most harmless app will need your permission to do just about anything... it doesn't mean it's out to get you. Firefox, for example, needs the permissions to save files to your phone, attach files from your phone, access the Internet with your account, etc. You've already found that denying these permissions will result in reduced app performance... if it works at all. If you are still hesitant about an app's permission requirements, feel free to contact the developer and ask why the app needs them.
keeping it close to the vest
