Vrakthris just posted this:
Maybe the squelch and silence are considered the same thing now that they’re back to actually suspending accounts for chat violations. Here’s the original announcement made for the introduction of the automatic squelch, back in 2007:
https://web.archive.org/web/20070528080211/http://www.wow-europe.com/en/info/faq/squelch.html
Here’s the article for the Silence Penalty system introduced in 2016: