The bold take is false and completely incorrect. I've discussed this with you before. I've even shown/posted you pictures.
Yes, when a defensive lineman is given a two-gap responsibility, his job is to quickly diagnose the play and pick which gap is the weak point. That is correct. The problem is, you don't seem to understand Rex Ryans scheme. Rex Ryans defensive scheme is not a two-gap scheme for the DL on every single play. It is multiple. They run combinations. Half the line could be playing a 3-4 concept and the other half could be playing a 4-3 concept.
Mario Williams did not have two-gap responsibility on every single play. He was asked to rush the passer plenty of times. Did Mario Williams have plays where he had two-gap responsibilities? Yes, he did. Is that the most effective way to use his freak athletic speed/strength? No, it probably isn't. Does that make Mario Williams mailing it in, ok? No it certainly does not.
It is entirely possible to not agree with Rex Ryans scheme and how he used Mario AND be upset at how Mario reacted to what he was being asked to do. Just because Mario didn't like the position/role he was being asked to play is not an excuse for the way he acted. Other players on the line didn't mail it in.