I have no doubt Alito was telling the truth about both memos. His statement that the role of a legal advocate is different from that of a judge is inarguable. He was writing as an advocate, and that is no less true if his actual legal opinion happened to be consistent with his advocacy position. It is also true, liberal cynicism aside, that a Constitution-respecting judge truly strives to (and does) separate his personal views from his decision making.
But based on today's unwritten rules that only inscrutable, stealth nominees need apply, I suppose Judge Alito would be foolish to volunteer his personal opinion (if it is his opinion) that abortion is morally wrong, or his personal legal opinion (if it is his opinion), that Roe was wrongly decided.
The problem is that if Alito answers the questions more explicitly, such as saying, "I believed then, consistent with my advocacy memos, that Roe was wrongly decided, and I still believe so today," he might be coming too close to telegraphing how he would rule in a future case. He can't possibly know in what context the issue may later come before the Court. He would also be giving the pro-abortion-litmus-test Left an excuse to filibuster his nomination. He has no choice, then, but to answer the way he did.
There is also the possibility, as has been suggested, that he believed in 1985 that Roe was wrongly decided, but that its presence in our jurisprudence for 20 more years weighs heavily against overturning it in 2005. Even judges who fashion themselves strict constructionists regrettably sometimes believe that longstanding Supreme Court decisions, even if erroneous when entered, should rarely be overturned.
Concerning Roe, liberals have a ray of hope with both Justice Roberts and Judge Alito. They both doubtlessly believe or at least believed at one time, personally and professionally, that the case was wrongly decided. But it is far from clear that either would overturn Roe today -- though I pray they would -- given their professed reverence for Supreme Court precedent and their reluctance to overturn even wrongly established precedent.
It's a sad state of affairs that liberal activist nominees, who are sure to uphold bad law, like Roe, when it suits their policy objectives, will breeze through the confirmation process absent a character or competence issue, but most Constitution-respecting ones will have a very difficult time. But in politics, double standards abound.