Jambler "has a feature advertised for taking property, improving its privacy somehow, and then returning roughly the same type of property"
Strictly speaking, it doesn't. Jambler doesn't act as a mixer, in and of itself. For partners, yes, it takes property, and yes it might return roughly the same plus a profit, but it nowhere says that it improves their privacy. The point of being a partner is to earn profit.
I could go on, but I don't think it matters, because it seems that you've made your choice. You could slightly change the criteria in the OP and it'd be rightly considered a mixer. You can't beat the admin.
you need to look at it in terms of US Law. Bitcointalk and theymos is subject to US Law.
Jambler aids and abets a mixer = fact
if bitcointalk aids and abets Jambler they could be charged with US federal law violations.
Best case I can explain it with is this article
https://www.hrw.org/report/2013/12/05/offer-you-cant-refuse/how-us-federal-prosecutors-force-drug-defendants-pleadit is about federal crimes mostly drugs ,but read the techniques the government used against people.
Theymos does not want any part of this.
I can't say that I blame him in the least.