If that was legally required of T-Mobile, don't you think it would be likely be legally required of all carriers? If that was true, don't you think there'd be a lot of people here confirming that Verizon and AT&T do the same thing? I am incredibly suspicious of the idea that this is a legal requirement, not a choice.
Sue them for aiding and abetting any crime that happens where one of the perpetrators carried a cellphone with their service.
"No, they clearly acknowledge their service is used for crime - they block these other messages."
For bonus points, find a case where blocking the 'weed' message got someone killed. (You order drugs, the guy says 'weed on the way' but you don't get the message so you don't meet him, he thinks it's a setup and gets mad ...)
