The last thing this place needs is someone who posts flames at anyone. You could easily have posted a link to the thread where he was trying to sell the sickly snake, or stated your opinion in a more professional manner. The way you posted it would not have made me believe in your so called gut instinct at all.
It's always better to behave in a professional manner, even when you feel a need to post that someone else may be a scammer. I'm glad that the guy was caught before anyone else was taken advantage of.
For the record, a trade of live animals is a contracted exchange of goods, and as such, you can indeed charge them with theft if they do not uphold their end of the contract. I hope you get him charged!
I think the high post count means nothing too. You can say a lot, while saying nothing of consequance the entire time. Doesn't mean a darned thing.