This is an interesting set of points which I'll need to think more about. My immediate reaction is that a) you overestimate the level to which the vast majority of people are actually influenced at all by the roots of the words they hear. b) The statement about the rabies vaccine isn't really accurate- it doesn't cure rabies. If you actually get serious symptoms the vaccine is essentially close to useless. The vaccine is given to people after they have been bitten because the immunity it induces can often be enough before the virus has had a large chance to multiply. We generally only do it in that circumstance because the immunity given is short-term, on the order of 2-3 years, and humans rarely get rabies now that we have largescale animal vaccination programs.

Your point about using the connotations of words to our advantage is an interesting one however that I'll need to think more about.