A lot of people blaming the poster, but I can say I've seen the same thing on completely opt-in lists that aren't doing anything shady. Reality is if you're only sending one email to your list a year, even when people want to receive it, it becomes really hard to send it to gmail. Especially if you're not using a shared IP with other senders. Gmail basically forces you to send messages on a quarterly (or better) cadence, even if you have nothing to say because otherwise it forgets who you are. I am convinced Google has a vested interest in making it hard to send newsletters and product announcements so companies will use their advertising products instead.