Not THIS time.

No.

The point is that by not opting in, we shouldn't have to do anything else.

Took me about two seconds to unsubscribe, and about as many mouse clicks. I think there are other causes more deserving of my moral outrage.

That is NOT the point. The point is that we have already made it clear by NOT opting in that we do NOT want to receive those UNWANTED emails. They have continued to send them. So WHY are we supposed to think that they are going to honour a second request to stop sending those UNWANTED emails?

And

a) given the number of threads on this topic I am NOT the ONLY person who is upset by this.
b) by NOT opting in WE shouldn't have to take any further action.
c) by ignoring our NOT opting in we have no reason to trust that they are going to honour a second request to opt out.

It's a combination of things. Because of the way our sales email client works and populates its send list, occasionally there is a miscommunication. No system is perfect, but given that there are probably 20 people bringing this up out of over 8,000 members who were active in the last month (so .25%), I'd say a 99.75% success rate is pretty good.

We send those emails to keep the site free to use and your address is not sold. Everything is done in-house. If you unsubscribe in the email, you should no longer receive them in the future.

Did you stop to consider that those 20 are the only ones who have decided to complain? And that there are plenty of others who are not complaining haven't reached the breaking point yet.

It's always possible. But you have reported your problem and received instructions for implementing a solution.