I'm in both camps, and I too don't want to respond to marketers. And the reason is so extremely obvious! I don't want to have to respond to endless questionnaires, either online or on the phone, and I don't want to be spammed! How is this a mystery?
I use the web all the time, to get access to all manner of information, including product spec sheets. Marketers should be able to notice whether their web sites are useful or not by the orders they get for their products.
And I also use the web to post my own work, so that everyone who needs to refer to it can access it. Of course, that part of the web is restricted only to those who need to know. But fundamentally, aside from the restricted access, this is no different from what product vendors should be doing. I don't send endless questionnaires to those who access my stuff on the web, nor do I spam them.