Yeah, Applescript in general is working, and the code snippet you pasted also works. I believe it's just the execute JavaScript part that's been disabled.
I completely agree with you, as is their purported reason (to "prevent disruptive ads", which to me, if someone is able to execute applescript on your computer, ads are the least of your worries).
They've updated it since I posted this, which is a good sign (the title of the ticket used to be something like "Add a feature flag to disable Javascript execution in Applescript"), but the logic of all of this is just really weird.
If they're disabling it by default on all of the developer friendly channels, why is it that average users wouldn't need that protection.
This is one poorly constructed ticket 