Stare decisis has never meant a lock on past decisions.
It is nothing more than a process one goes through to analyze precedent according to stated principles, and certain weighting is given to the various criteria. To say one is wedded to stare decisis is to say they are wedded to that process. It is a careful, meticulous process of consideration. The final result can still be, and has been in previous cases, an overturning of past rulings.
In his testimony, John Roberts gave the same deference to the process of stare decisis. Some jumped straight up and said, oh look, he is stating that he could never vote to overturn anything, not just Roe, but Kelo (property takings ruling), no death penalty for anyone under 18, etc. Cooler heads prevailed as the truth was pointed out. He left plenty of room to overturn anything.
His support of the careful process of consideration and weighting in no way precluded that.
The problem with using Justice Roberts as an example in these discussions is that we don't yet know how he's going to turn out (and won't for at least, say, five years). Scalia may be a better example of someone who supports and applies stare decisis (although personally I prefer Thomas, the staunchest originalist).