Delivery of Javelin, Stringer, TOW-2 and AGM-88 to ROC has already been delayed due to this war, why not M1A2T.Any trained personnel, equipment, parts, & facilities General Dynamics already has committed to existing orders would also have to be diverted to make those Ukraine bound tanks fit for service. So there's a question of priority and whether you delay deliveries to other customers.
In other news:
I've suspected as much before that ISR help is the easiest way for China to help Russia. I don't think sanction in this case will help Ukraine, as this company is now going to go "fuck it I'm already sanctioned, I'll sell any satellite image you are interested in"