I followed up on these and this is what I found:
The U. S. Treasury Department denies asking satellite ISPs to block access to customers in Cuba and Cartas Desde Cuba did not reply to my email asking for the source of their report. That leaves me with no reason to believe the charge that satellite ISPs were told to cut off Cuban accounts.
Coursera is one of three prominent U. S. sources of massive, online educational material. I followed up with the other two, edX and Uacity, to see if they had been told to block access to their material:
EdX: They applied for a Treasury Department license without being asked to and it was granted (after seven months).
Udacity: Google serves their material, and as far as they know, it is not blocked. I asked Google, but they did not reply. (Google never replies to me).
Coursera: They were asked by the Treasury Department to block access, but they are seeking a license to serve blocked nations.
Overall, the Treasury Department seems willing to grant these licenses (as with edX), but evidently wants to review each case (as with Coursera). Either way, the process takes a long time. Furthermore, how many organizations unilaterally censor themselves in order to avoid problems? This feels more like bureaucratic rust than an intentional policy, but blocking or delaying access to free educational material is a bad idea -- they should clarify the policy.