Absolutely nothing!

Art is a very subjective thing.  What is art to one person, isn't necessarily art to another person.

You aren't going to change their opinion, so why even bother trying, or even worrying about what they think? You don't need to defend your choice of materials/programs to produce what you consider to be art.

"It is good to see ourselves as others see us. Try as we may, we are never
able to know ourselves fully as we are, especially the evil side of us.
This we can do only if we are not angry with our critics but will take in good
heart whatever they might have to say." - Ghandi