People are regularly judging one another. It's a way to mitigate personal harm. People often shut out an opportunity because of fear of failure, or wasted efforts. It has nothing to do with you or the opportunity.
It has everything to do with their own judgement and concern for personal well being.
What matters is, next time they hear about bitcoin or cryptocurrency they will have heard about it once before! Well done sir.
Sometimes the best thing you can do is say "Check out the new social media site they are calling the fakebook killer". Let them find out for themselves how to make money ;-)