People on the blocked Telegram channels have denied the Holocaust (including the channel operator himself) which is a crime in Germany, Austria and 16 other European countries [1] or called for the murder, disfigurement or other injuries to politicians [2].
"Anti-mandate discussions" are bad enough, but unlike what went on in Hildmann's channels this stuff isn't criminal so the comparison of yours is a bit wrong.
[1] https://de.wikipedia.org/wiki/Gesetze_gegen_Holocaustleugnun...
[2] https://www.faz.net/aktuell/feuilleton/medien/hunderte-morda...
On the other hand, forcibly removing content for the sake of the content is censorship. It can be censorship that most people approve of - which they usually do when the content is sufficiently vile and irredeemable - but it's still censorship.
And yes, content was censored on. But not only death threats were censored but also holocaust denial, eugenics and inciting hatred against ethnic groups (Jewish groups, specifically).