Twitter account authorization

With Facebook and Linkedin you can use the api credentials of an app, to authorize any Facebook/Linkedin accounts and post on their behalf. But there is no similar option when you add a twitter account. For twitter it only posts to the twitter app owner’s timeline and you can not authorize any other twitter accounts to post on their timeline. Is this a limitation by Twitter or just not yet implemented by SNAP plugin?

http://ww.wp.xz.cn/plugins/social-networks-auto-poster-facebook-twitter-g/