The messaging could have been clearer but I'll spell it out for the dumb.
Phase 1:
Don't panic buy medical supplies expecting them to protect you. We don't have enough, and frontline healthcare workers need them to protect themselves and others, you don't know how to wear them and they probably don't fit you properly.
Phase 2:
We still don't really have enough medical grade masks but just fyi: any sort of mouth covering will reduce the risk of a contagious person sneezing into the mouth of a vulnerable person. If you have to go out, please wear something over your face. Cotton is better than nothing.
Phase 3:
A tight fitting mask really is best, it limits a contagious person's generation of aerosolized clouds of viruses, and limits a vulnerable person's exposure to clouds of aerosolized viruses.