Instead I'd write a successful application in it. Usually showing people they're wrong is more effective than telling them so.
You can prove them wrong as many times as you want and if your language isn't spelled J-A-V-A or C-# then it doesn't matter how many 9s of uptime you can easily achieve or how much scalability you get for free to them. They've already discounted it in their minds and they're just using industry bullshit-speak to explain it.
I would love to punch Hani Suleiman in the face.
Why prove anything to anyone?
Just build something cool, make $$$,
move on, build something else cool and make $$$, ....
the more people who use something, the easier it is to use it to build products.
I don't agree. The ability to build products doesn't depend on popularity of the methodology. It's more about your creativity, diligence and willingness.
I think you'd be more likely to get arrested for that than proving your point.