Coupla points there.
Firstly I wasn't advocating passive resistance or stoic forbearance as the correct course of action in the face of abuse
per se, I was pointing out to Richard that it doesn't necessarily require a "macho" response. I personally have no objections to sportsmen giving the crowd a bit of comeback (within reason, obv). To use a very recent example from another sport, Mido the Middlesbrough striker who's an Egyptian Muslim, copped far worse (seriously, Google it) than Murali has ever got from the Newcastle fans & his response on scoring a goal was this:
Not an aggressive gesture, just a "silence, morons". I think any fan of a team a sportsman represents would prefer this to Murali's course of action.
Secondly, I'd say it becomes unacceptable when it becomes racist or extremely personal. Yelling "no-ball" doesn't qualify on either count.