The problem with that "make it yourself" argument is that there people that very much do it. We criticize because we have a FRAME OF REFERENCE. This basic RGPM walking sims are not some new, avangard field - so are the shoes, and bread, and restaraunts, and whatever else parallel's are being made when this laughable argument get's brought up.
Case in point, there developers (mostly japanese, quite telling) that released finished RPGM games (hell, some even multiple) in the same span of time it takes this one to make 2-3 shoddy maps and a couple dozens lines of dialogue.