Have you worked in a startup environment?
In any early stage startup, you need to be ready to roll out your sleeves and ready to do anything awesome in the interest of your team.
This might be getting new leads, contracts, deals or whatever. This is how all great companies started.
This should be the attitude.
And please don't say - I'll only do this and not that. I will never hire you or work alongside such minds.
Its the role of founders and early team to nurture the project and processes.
Startups are very low on budget and can't spend $$ for sales or MBA heroes. Today developers can write a great blog article and attract customers in your niche.
Note: We are all full-stack developers and completely bootstrapped. We have failed and learnt things the hard way so far. Once things are setup we have plans to invest/hire dedicated staff. We believe in training and making them align with our vision.
I think you might have never worked in a startup, so you don't get the idea and feel of it. :)