Sounds like a serious threat. Better cave.
It sounds to me like the CEOs have been eating their Wheaties and reading up on their Ayn Rand... Seriously, though, I love how the letter makes it sound like all the brouhaha is coming from a "concerted publicity campaign by some advocacy groups". I just looked at the FCC's public docket for response to Wheeler's previous proposal, and there are at least 10,000 responses. Even my state of Tennessee, not necessarily the most friendly to to Federal regulation, had 500 comments. I looked at a random sampling from TN, and couldn't find one posting with any particular love for the current regime of large ISPs. Words like "oligarchy" and "monopoly" were quite common.