Except that Wisconsin allows in-person registration on Election Day, which means that if they mailed in forms thinking they were registered for the primary, they'd show up on primary day and be turned away; and if they thought it was for the general, they were falsely dissuaded from bringing their paperwork to register for the primary on site. Link
Repeatedly, they've been admonished by states and by voter complaints about (a) registering voters for the general after primary deadlines and before the primary election, and (b) calling anonymously. They vowed to fix the second, and didn't.
Moreover, add the problem (at least in NC, dunno which other states) of contacting registered voters with a phone script that made them believe they were registered, and you've got something with very bad effects in NC, however well-intended.
Whether this was coordinated with the Clinton campaign is entirely separately from the main question: was this negligent or deliberate? And given the number of states in which they've made calls during primary season but after registration deadlines, I do lean towards the latter, but am open to listening.
Um, calling in the middle of the primaries and not specifying in the calls that this program is for the general election are good reasons why "some people ... are thinking the group is focusing on the primaries rather than the GE".