overcoming ignorant people
1. throw chalk in face
2. right hook
3. shoot for legs
4. move to back
5. rear naked choke
stops the drivel in about 20 seconds flat
Seriously though, I give everyone about 2 minutes of my time and if it's clear the conversation is going nowhere i just excuse myself politely and go back to lifting twice as much as they do.
You can't change everyone, the ones who are worth expending effort on will come around quickly. Also be aware of the fallacy of using grades etc to compare yourself to people.
By all quantitative measures no one on earth should be listening to me talk about training because i've been a rubbish athlete all my life but I get results for people and that's all that counts.
People who have opinions that run counter your own beliefs can also be useful in challenging your assumptions and you'd be surprised what you can learn about your own beliefs and methods by having them reflected in a mirror of stupidity.