I say "assuming" because many times I'm communicating with people who don't necessarily believe in evolution, and I'd rather not derail my thought experiment with an argument over whether evolution is real. Instead I have the argument with pompous believers of evolution who scold me for being respectful.
The disrespectul terminology says a lot. Evolution is not a "belief", is a fact and yes, I'm aware that you know it.
There is a skyscrapper of scientific articles documenting it in every coin of the planet, by entire generations of people from each nationality. We are aware of the existence of dinosaurs since more than 345 years ago. Darwin explained evolution "for children" 160 years ago. Most of his picture is still valid and relevant, accumulating proof after proof and expanding and gaining complexity and resolution since then.
Don't fall in the trap of disperate attention seekers or trolls. The only question for people that choose not understand that evolution is real in 2019 is: What is your excuse for lying to yourself?
Nobody says "lets assume that maths are true" or "lets assume that computers really exist"