What the campaigns signified was the blessing of St. Peter through his successor, the pope, of military action: it was a public 'sanctification' of war or warlike measures
The break with the East was not yet 20 years old when Gregory became pope, but his mind was already actively engaged in the planning of a military campaign against the East
Gave Peter (who assumes a primal papal role) the ability to speak 'ex cathedra', meaning to speak as Christ's representative on Earth. His words were thus infallible.
In this Paul preaches that who is doing the teaching is unimportant, it is what they teach (and whether it aligns with what God intended) that is important. Thus despite the RCC's ruling on receiving anathema for rejecting the Pope, it is only those who teach incorrectly who get cursed.
Gregory VII: '"We may avail to recall him to the love of the holy Roman church which is his mother, and to instruct and adorn him in a befitting manner of life for receiving the imperial office"'
Gregory VII: '"I deny to King Henry, son of the Emperor Henry, who has risen up with unheard-of pride against your church, the government of the entire kingdom of the Germans and of Italy, and I absolve all Christians from the bond of any oath that they have taken, or shall take, to him; and I forbid anyone to serve him as king."'
Gregory VII: '"And therefore I believe it to be by your grace and not by my works that it has pleased, and does please, you (St. Peter) that the Christian people entrusted especially to you should be obedient especially to me through your vicarship committed to me."'