I don't trust Facebook or Twitter to distinguish disinformation from information. Why would anyone?
Anything that collects a mass number of likely untrained/uneducated people in a common space, where they can create a post record of anything with no restriction of content to the world at large, will never be a serious source of news or foundational information. You may sift through this and get something useful or interesting once in a while, but it is simply incapable of as a whole of being anything great.
The fact that these networks exist as primarily ad businesses is probably the best thing that can become of them.
The most useful/meaningful thing totally free/open social networks can do in a general sense is provide a venue for people to post raw media of events, such as crimes, etc. which can be useful if you are near that locality, but the comments and subsequent discussion have a very low chance of being anything but emotional expressions.
I am fine with whatever actions Facebook or Twitter take to do this if they feel the need. Facebook and Twitter are not government agencies. People choose to use them. People whine and bitch about how everyone they know are on Facebook and Twitter, but alternatives do exist and it is possible to use them. You can also just text/SMS your friends and family.