Did you try the TLD's administrative contact and did you make sure you are using tools that report to Spamhaus or other blackholes?
.bid seems to be 35% bad which is not all that bad if they have been offering $1 domains for long. So maybe they take some actions through the registrars to stay bellow being presumed spam by default or maybe not enough of these unique domains are getting reported..
Why do you think it's a monopoly? I think SMTP is more often on premises at organizations than web services for example.
The hoops to send have existed for a long time and simply evolve. A push protocol without trust is a pretty bad idea after all.. So bad the fax machine needed the legal system to inflict severe punishments for the physical resources consumed by unwanted push (in theory if not practice.)
.bid seems to be 35% bad which is not all that bad if they have been offering $1 domains for long. So maybe they take some actions through the registrars to stay bellow being presumed spam by default or maybe not enough of these unique domains are getting reported..