A few random comments:
Trinity Church's facility is a regular church facility, not somebody's house with a sign put up and taken down on Sundays.
Mark Driscoll is a rather controversial figure, but setting that aside, being susceptible to bullying and excessive subtlety are not among his flaws.
A proper government notification would have specified the ordinance violated, in what way, and possible means of compliance (besides simple removal). The email sounds more like a Christian-hating bureaucrat trying to bully a church.