This is really weird. They were blocked once, but I tried these again ~40 minutes after my original test, and they went through. Then, when writing this comment, I tried a third time, and they were blocked again.
First run: odysee.com, jacobinmag.com, itsgoingdown.org were blocked. I did these just before midnight EDT.
This second run: odysee.com, and freethestates.com (didn't try it the first time) were blocked, but jacobinmag.com and itsgoingdown.org are not anymore. I double-checked for spelling mistakes, etc. I also checked covidcarealliance.org and lichess.org, also blocked. I also checked goo.gl URLs (previously notoriously blocked by T-Mobile) and they are not blocked.
I did some looking into this, and T-Mobile employees have been surprisingly open about URL filtering in the past on their support forums. One example (see https://community.t-mobile.com/accounts-services-4/tmobile-i...)
> I’m taking care of this right now. I must say the domain is very amusing and creative! It’s flagging for a combination of issues: collocated with Amazon AWS with 5k other domains, registrar to Namecheap (poor reputation with DGA generated domains), and inserting both URL and email address in message body. (double whammy). Otherwise, you are following proper protocol with Twilio A2P messaging.
>
> I’ll have the vendor reputation resolved in a few hours. Thanks!
It's surprising to me that AWS and NameCheap are named as contributing factors.
In fact, writing this comment took so long that I tried the strange URLs a third time. jacobinmag.com was blocked again but not itsgoingdown.org. So, jacobinmag.com has flipped from blocked, to not blocked, to blocked again in the span of an hour.