There are some small differences.
1. Arnold became a turncoat for several reasons, money being one of them I believe.
2. Because he was an outspoken opponent of the U.S. role in Vietnam long before he ever enlisted and served. it's highly likely his main reason for enlisting was to establish a political resume for himself. At least Arnold believed in what he was doing prior to his changing sides.
3. Arnold left the United States, and for the most part was snubbed for the remainder of his life by the British who believed he couldn't be trusted.
4. John Kerry on the other hand, made successful political hay from his turncoat and traitorous activities...not to mention mucho bucks.
Excellent point! I hope it gets used.