Founders' emotional reactions to criticism aside, isn't one of the chief benefits of releasing quickly the market input? One can feel sad about that feedback or, after properly weighting it, parse it as the valuable guidance it is.

The markets provide cruel, ruthless feedback in the form of buy/pass behaviour. Getting that feedback as early as possible on one's MVP is insightful, albeit painful. Criticism can be more valuable than atomistically binary market activity by providing insight into why the market is behaving as it is (or will be).

Given the specific case, if the founders are working on a feature to fill the hole discussed, great - they have a bit of validation. If not, they have the opportunity to consider it. Either way, I don't see why there is a reason to get beaten up about it.

Negative feedback is as much a drag on innovation as market rejection. At worst, it should be a non-factor.