An actual response I got from a cold outreach:
"We are a bootstrapped startup with zero funds and zero employees.
What do you want from us?"
Listen, I hate cold outreach emails as much as the next guy, but either ignore or unsubscribe. Given that you're also a startup you should understand the need to market your services, or you're not going to get your own business off the ground. Hostility like this isn't going to bode well for you in the long run.
For the record I responded saying we were just advertising our services, but clearly they're not in a position to make use of them, and I wished them well in their venture. Looking at their site it likely won't be long for this world and they really could use a hand, but to each their own.
We're not aggressive with our emails, it's an initial outreach then two follow-ups and done. You're free to unsubscribe or say no at any point, but this is just rude.