Are you sure? Most users there seem to ask to avoid messages to users immediately after registration, rather than messages altogether.
Perhaps it's enough to set NewUserMessageOnAutoCreate to false, for instance.
This is entirely possible to undeploy it, but we need a consensus for that.
The configuration change done is the minimal set everyone seems to agree on, and a first step while you reach an agreement.
Could you address @Nemo_bis concerns about how the discussion on Babel should be interpreted?
Again, the community reached a consensus to remove that welcoming system from Meta. In fact there's the only consensus gauged there. We don't want automatic welcomes anymore.
The discussion was publicy held, and Nemo (who is very active at Meta FWIW) or anyone else could have commented there proposing other solutions. He didn't, and trying to block this at Phabricator is disrespectful, specially when in less than 24 hours there was far more consensus to get rid of the system rather than to enable the extension.
We're not requesting any critical or strange change in config that warrants a block by ops, but to undeploy a nuisance of extension as the people who commented in the discussion explained.
Please enact the valid community consensus and undeploy this extension at Meta. The account will remain blocked until then. Thanks.