I am completely baffled and bamboozled by this entire story according to Rashi. Was Aharon at fault or not? According to Rashi it seems like he was not, but then the Torah continues by saying that Moshe was angry at Aharon and Aharon was the cause of the disgrace to Israel. How, then, could Aharon be innocent of this sin?
The Ramban realized this difficulty in Rashi and therefore said:
(כא): מה עשה לך העם הזה כי הבאת עליו חטאה גדולה -
כמה ייסורים סבלת שייסרוך עד שלא תביא עליהם חטא זה. לשון רש"י.ואיננו נכון בעיני, כי החטא הזה מן החטאים שייהרג עליהם ולא יעבור. ואולי אמר לו כן להגדיל אשמתו.
והנכון בעיני כי הוא כמו מה עשיתי מה עוני ומה חטאתי לפני אביך כי מבקש את נפשי (ש"א כ א). יאמר, מה שנאה הייתה לך עם העם הזה כי סבבת להשמידם ולכלותם. ומפני שהיה אהרן להם לאיש מוכיח ולמכפר, והיה ראוי שיחוס וירחם עליהם, אמר לו כן.
Loosely translated this means: This can not be correct since this sin that Aharon committed is Idol worship which is Yehareig vial yaavor (Be killed and do not transgress). How then can he blame the people for "forcing" him to do it, he should have died rather than make this golden calf. Therefore, the real meaning of this verse is not that Moshe was calling Aharon a victim, but the perpetrator of this heinous crime.
The Ramban tells us what really happened in this incident:
ויתכן שגם משה נכון לבו בטוח בצדקת אחיו שכוונתו לא הייתה רעה, אבל על אשמת העם האשים אותו, כי היה ראוי להוכיחם והם נכשלו על ידו. והוא השיב שהטעוהו בדבריהם:
He tells us that Aharon's intentions were pure and the pressure of the nation got to him, so he caved in. True, Aharon did make the Golden Calf, but every step of the way he tried to deter the nation from worshiping it. He tried to get them to attain gold from their family, but they used their own. He tried to get them to focus their efforts toward G-D by making a holiday to Hashem, but they sacrificed to the Golden Calf. Aharon thought he could control the situation, but he could not.
The fault of Aharon was that he thought he could handle a situation that was too big for him. This is why he says to Moshe that the nation is an evil people. Aharon was Mr. Optimist, what happened that he all of a sudden called the Jewish people evil? He was frustrated and let down that they followed through with their evil plan instead of allowing him to deter them.
The most valuable lesson we can learn from this is understanding our own limitations and how to respond with that. Aharon should have told the Jewish people that he would not make the golden calf no matter what. Had he done that then he would have totally prevented it or he would not have been involved at all. By involving himself, although his intentions were good, he legitimized the golden calf. This most probably allowed even more Jews to join in by thinking that Aharon was the one that created it so it must be kosher. Aharon bit off a little more than he could chew and this is why Moshe was angry at him and asked him why he caused the nation to sin. It was Aharon's involvement that caused the greatest Chillul Hashem (Desecration of the Name).