It now seems that Facebook is blocking attempts to share or re-post content from sites that are involved in the March on DNC and other protest groups, by blocking users from sharing those posts and displaying to them the following message:

The action attempted has been deemed abusive or is otherwise disallowed. To keep from getting blocked again, please make sure you've read and understand Facebook's community standards.

Here is a screenshot of Facebook censorship of sites related to Sanders and the related rallies, marches and events planned to coincide with the Democratic National Convention in Philadelphia:

This is either something that Correct the Record (or other trolls) are doing to disrupt the events planned to support Bernie and oppose the DNC in Philadelphia or someone at Facebook is intentionally trying to censor these sites. Note that this user also refers to porn being posted on Bernie sites, as well.

The lengths to which they are going to shut down dissent regarding the presumptive nominee, Hillary Clinton, and our corrupt pay for play political system in the Democratic party, have reached ever more ridiculous levels. I, for one am sickened by what I am seeing over the last few days, even as we learn more about how the DNC and Clinton campaign worked to embed false narratives in the media about Bernie from the documents released by the Guccifer 2.0 hacker.

Appalled is not a strong enough word, nor disgust, nor repulsed. Ashamed of my country for falling into such a state where we are as bad as any "banana republic" that ever existed, and angry at the depths to which these guttersnipes will go to keep the people down and serve the One percenters.