That's not entirely accurate. As the notice says, this particular lawsuit was filed on behalf of a particular group of writers and editors who were "required... to falsify time cards, failed to [be paid] overtime and routinely required... to work 12 hours a day or more" (and who are, presumably, a part of the WGA already, or else the WGA probably couldn't have filed suit).
It mentions that other lawsuits have been filed by other writers, and that the WGA has threatened to strike against studios if certain positions (story editors, producers, etc.) are not overhauled to be more in compliance with their actual functions (wherein they "write" the shows through editing, etc.).
It's not clear who the "12 writers" who sued last month are- whether they are involved in the "reality show" trade or scripted shows.
Otherwise, yes, this is largely about the WGA seeking to protect the interests of its laborers (and itself) by demanding stricter regulations on the reality genre.