The reason the committee did what they did, was the time-line.
- Hole 15: Tiger makes an illegal drop
- Hole 18: A viewer makes the officials aware of the issue at 15
- Hole 18: The committee decides Tiger did not break any rules and does not confront him with it
- Post-round interview: Tiger says he moved two yards back on purpose
- Post-round: The committee sees the interview and realize they made a mistake not confronting Tiger with the illegal drop. They discuss it and in the morning contact Tiger to talk. The committee give Tiger a two stroke penalty for the illegal drop and Tiger accepts.
The committee issues a statement, with the following words:
The penalty of disqualification was waived by the Committee under Rule 33 as the Committee had previously reviewed the information and made its initial determination prior to the finish of the player’s round.
Here is the general text of rule 33-7, which leaves the decision to the committee.
33-7. Disqualification Penalty; Committee Discretion
A penalty of disqualification may in exceptional individual cases be waived, modified or imposed if the Committee considers such action warranted.
Any penalty less than disqualification must not be waived or modified.
If a Committee considers that a player is guilty of a serious breach of etiquette, it may impose a penalty of disqualification under this Rule.
Given the circumstances, the committee decided it was not a serious breach, and I've come to accept that. Tiger did gain an advantage, but not a very big one. He had to hit the same shot, just a few yards farther back. Some might say it's a disadvantage, but since Tiger consciously did this, we must agree it was to gain an advantage, but it was probably not deemed a serious breach. The important part, as far as I believe, is that the committee decided it was not a breach during play. They should have confronted Tiger with it before he signed his card, but failed to do so. Upon watching his post-round interview, they realize they made a mistake. Given all these circumstances, the committee decided it was too harsh to disqualify Tiger - the subject was not even on the table - and give him a two stroke penalty. Partly due to their wrongdoing in not confronting Tiger before he signed his card.
Some might say it's a stretch of rule 33-7, but it is what it is. Personally, I think the decision not to confront Tiger with it during his round was the determining factor.
As far as Tiger's legacy goes and whether people will "accept" a win today is not a concern of mine. If he wins, he wins. He's taken his penalty and moved on. We can discuss the events in hindsight, claim the committee did a poor job and question the wording or interpretation of rule 33-7, but Tiger has done as he was asked to do.