They are all Wotc employees in a certain sense. All of them are supposed to work for the good and benefit of Wotc. Unless you mean that "the suits" may possibly want to "tank" Wotc for some reason I cant see where your point is.
They may all be WotC employees, they may all want WotC to do well. But I think a lot of people refer to the nameless suits because they see them as different sorts of employees than the creative R&D sorts. And they are. They are, compared to designers with by-lines on products, nameless to the consumers of WotC's products.
Whether or not they actually wear suits, they are assumed to be the middle and upper management, accounting, legal, etc. The further implication of the people using the term is that these are the employees most focused on WotC as a business venture rather than as a creative venture, in no small part because that's what their roles at the corporation focus on. Running the business, not game design. They may need to run the business-side of things effectively to enable the game design to flourish, but their focus and practices are insulated from the nature of the end product. They'd do many of the same things whether WotC was publishing games or cookbooks in protecting the IP, researching effective marketing tactics, running the HR department, and so on.
That's what I figure people mean when they talk about nameless suits. And comments about Dilberteque views of the world aside, different job roles produce different views and interests in the practice of the business even if all roles want the business to succeed. And you can see it in plenty of other corporate bodies as well, not just game publishers like WotC. People assume that these "nameless suits" at WotC and Hasbro have their say on the way WotC runs their business and have few other ways to express it since we barely know who any of these people are and their decision processes are part of the inner workings of WotC and generally not appropriate for WotC employees to share.
So what do you expect people to do when they want to complain or comment on decisions that they suspect come out of levels of WotC structure aside from R&D?