It is by definition not spam, because you asked for it. You said "I want that PDF, here is my email, please send me that PDF (or newsletter or course or whatever)."

You are obviously fully within your right to unsubscribe later, including immediately after downloading said PDF, but it's not spam by any real definition.

Only because of a dark pattern that obscured the fact they would continue to email me.

Regardless it's utterly ineffective. It goes straight to the trash.

There is no reason whatsoever to ask for an email other than to continue to email someone. Unless you're signing up for an account (which is a completely different flow), no reasonable person could honestly expect that they're just giving someone an email address so that they can get a PDF link and that that will be the end of it.

Which is precisely what happens. They always ask this question when you sign up for an account.

You don't represent the way a majority of the world thinks. It's important to remember that being someone that creates software for people

Actually, I do. The rate of sales to number of emails sent is minuscule. That's why there is so much spam!