Nowhere is it written that your critique can only be taken seriously if you fix the problem you discover, propose an alternate model, or solve the problem outright. By your logic, all the people from the 1800s on into the early 20th century who said, "You know, Newtonian mechanics has a serious problem: it cannot correctly describe the precession of Mercury" were doing a poor job of critiquing Newtonian physics.
Rubbish. They were doing a superb job of critiquing Newtonian physics by pointing to something in the Newtonian model that was clearly, unambiguously, wrong. They may not have been able to realize why it was wrong or able to construct a better model, but they pointed out an important anomaly. Later on, Einstein came along and proposed General Relativity, and one of GR's greatest initial successes was its ability to correctly model the precession of Mercury.
If John Christy's reading of the facts is in error, then that's ample grounds to say he's made a poor critique. But to say that he's made a poor critique just because he hasn't fixed the models, put forward a new model, or explained the differences between model and observation, betrays you as a very poor scientist.