Yep, Eschatonic, smallcompany and netmeg have it right. You're not buying something as if going to the store and buying a t-shirt but given the privilege to use the system. As with any other privilege, it can be taken away as opposed to the t-shirt which cannot once in your possession.
I can understand support sometimes leaving a bad taste. Been there myself and I'm sure most of us. But advertisers must do their due diligence. Complaining about it doesn't solve anything. From iguru's posts, there appears to be no misinterpretation of the business model and is in violation. It can take months, years even, for Google to get around to audit your site. Best thing to do until they do is make sure it will pass the audit.