I think most of our disagreement is overly technical at this point, but I do take issue with a couple of things you said:

Quote Originally Posted by foa
Yes, but the opinion in Brown v. EMA advises 1) video games are protected speech because they fall under the protections due to media and 2) also encourages as the industry grows the decision be reexamined.
I take issue with point 1 to the extent that it seems you're implying that's a distinguishing feature from t-shirt messages (see: Cohen). Additionally, Brown said the opinion could be reexamined based on future evidence based on California's argument that the interactivity of video games make it distinguishable from all other media -- not foretelling a reexamination of the entire First Amendment doctrine of the past 50 years. See also Erznoznik v. Jacksonville.

Quote Originally Posted by foa
[insert Miller test]
Quote Originally Posted by me
Unless it fits into an obscenity exception...
The obscenity exception is also garnering less and less use in modern times. I can almost guarantee that none of the t-shirts qualify as obscenity today, not even in the extra-bulltrout "obscenity as to minors" sub-category of the Miller line of cases.

Big difference between a political dissent and a tshirt that advocates fellatio or something. Different types of speech aren't protected equivocally. You know that.
Not as much as you seem to imply here, especially (as here) where the law at issue focuses exclusively on content. Unless the ban only impacts obscenity, a content-based ordinance would still face strict scrutiny as a rule, which is de facto invalidation (and it should be noted that even if some of the t-shirts are constitutionally obscene, the ordinance is still facially unconstitutional to the extent that it applies to any protected speech). There have been plenty of vulgarity/profanity bans that have been struck down over the years, not just in clear-cut political speech cases like Cohen (and I would argue that almost any advocacy on a t-shirt, no matter how trivial it may seem to others, is political speech under the First Amendment anyway).

And I should note that I'm not saying that all of the t-shirts would be necessarily protected speech under the First Amendment, because I haven't seen all of them (although if any store owner is willing to display them in public, it almost certainly would not qualify as obscenity). I'm only saying that the ordinance is unconstitutional. It would only be constitutional if it was interpreted to only refer to legal obscenity, in which case it likely wouldn't apply to most/all of the t-shirts the mayor hates.