I think you're being overly generous, @tdelillo . At least three of mine say they are from "Instructure Partners", have an noreply@instructure.com address, and have a web-bug from info.instructure.com.
Of the ones that didn't come from Instructure directly, one said "I see you are presenting at InstructureCon". Another said they were excited to see I was joining them at Hack Night, but that was from one of the Hack Night cosponsors after Kona signed me up. I don't know if if there was an opt-out there for Hack Night or not since she filled it out.
Chris' Jive login doesn't have his email as his login, it just has /people/chriscas, although when you go there, you can get it. So, if they are getting it off the web, they're doing an extra bit of scraping -- either that or someone is and then selling the lists.
All of the ones except for the "I see you are presenting" had an unsubscribe for me.
So, while it may be public information gathered from the forums here, it definitely reflects badly on Instructure -- if for nothing else than choosing to partner with these companies that send the unsolicited commercial email.