You may some good points, and we address a right to free speech in the main article.
I believe there is a right to anonymous speech, but when you're paying someone else to speak for you, and you're trying to influence the political process, that may be different.
An anonymous poster on Slashdot generally isn't trying to be something he's not. Anonymous speech online (or elsewhere) generally doesn't carry with it an air of credibility that advocacy groups and think tanks try to project.
I should also note that our reporting looked at groups both in favor and opposed to strong net neutrality rules. Generally, groups in favor of net neutrality got better transpaIrency grades, but we looked at both. We weren't targeting one side, and a handful of pro-net neutrality groups received mid-level or lower grades.
[Here's our sidebar rating the groups.
Finally, our reporting, while taking a lot of work, didn't really unmask or shame anyone. We used information that was generally publicly available from the groups, if in many cases, hard to find. I'm not sure how that amounts to shaming.