I called the Catelyn scene terrible and embarrassing because it (in the context of other changes made to the character) reduces Catelyn, who in the books subverts fantasy tropes by being assertive and politically savvy but not the stock woman warrior or spunky princess, to someone who frets over being a good enough mom, even when the person in question is not, by the standards of the society, her son. Part of what I admire about A Song of Ice and Fire
, and part of what people praise about Game of Thrones
, is that it's honest about the grittier, uglier aspects of medieval life, rather than projecting modern values onto a feudal society. But in a feudal society, Jon wouldn't be thought of as Catelyn's son or stepson, and no one would have expected her to love him or suggest he be legitimized. The whole drama of the scene is contrived, and serves no evident purpose except to make Catelyn look bad. If they wanted to show her feeling unreasonably guilty, there are plenty of more concrete things she could, with hindsight, regret.
It's especially baffling since the series had previously downplayed the awkwardness between Jon and Cat by removing the "It should have been you" line from their scene in "The Kingsroad" (which was, given the difficulty of communicating her mental state at the time, a reasonable decision). But this makes her general attitude toward Jon far nastier than it was in the books. It's not the worst thing in the world, but it's another bad decision in adapting one of the few characters in the source material who really deserves the series' reputation for breaking with conventions.