I don't think most people have been explicitly talking down linear adventures -- although their is the usual conflation of linear and railroad. I do think that those of us who prefer sandboxes try and defend them against the common charges of sandboxes not actually being possible at all, or impossible to play because players get analysis paralysis or whatever.
Linear adventures are great, IMO, for groups like my Monday night gang that just want to get together and play. People want to have a whiskey and stab some monsters, maybe put on a funny voice. Not all linear play is casual, of course, but linear play is good for casual engagement.