The article is from an old date and got no updates, security is a moving target so it is outdated.
a debunk is not existent, thats why I miss it.
I requested such an article of Mozilla devs long ago. There is a damn bugzilla thread, which helps a bit, but it needs developer documentation or something.
Torbrowser needs to be secure. If the browser source cannot be trusted, or if Mozilla can be trusted more, then it makes sense to use it.