I think a focus on the issues is exactly what is being called for here.
For example, one issue is that the mainstream media very often relies on flawed research or very narrowly defined research questions to then make broad claims about an entire population. When that happens, it is important for critical voices to speak up.
Another issue in the case of sex work in particular is that there is a great deal of variation in working conditions, autonomy, risk, and so on across the "industry." To take the situation of some of the most vulnerable sex workers and then use their stories to support overreaching claims about how exploitive and dangerous "all prostitution" or even "all sex work" is, is irresponsible at best and conscious deception at worst.
It is true that Melissa Farley's work will certainly be directly criticized during the proposed blog-in. That is precisely because well respected journalists and columnists, like Bob Herbert, have relied heavily on it without revealing to their readers any of its weaknesses. Readers need to know as much about her research as possible if they're going to be using it to formulate or support their opinions.
So is this a smear campaign? It doesn't sound like one so far, and I'd bet given the intelligence of the people at Desiree Alliance that it won't turn into one. It is a broadening of the discourse around sex work to include a range of voices and a critical perspective on the mainstream media and its sources.