This is what Prophets do!
John the Baptist's ministry serves as a pivotal point in the timeline of biblical events, marking the transition from the Old Testament era to the dawn of the New Testament. (Quote sourced from Christians.net)
Set aside before birth John's divine purpose was to introduce The Messiah, the Son of God. John had no microphone and spoke from the desert. Yet, crowds flocked to him.
John's success made him enviable as a recruiter and risky to the religious gatekeepers. But, he knew 'his troupe of disciples' were not for his glory but the Lord's.
John the Baptist would exercise his call by exalting his own disciples to Jesus with:
He must increase and I must decrease. (John 3:30)
John the Baptist called for repentance. Jesus' first recorded words in Mark's gospel commanded repentance. This is what prophets do - call for repentance.
In understanding John the Baptist we see humility and courage personified. Surely, all who would prophesy would first be humble? Remember the Lord is far from the proud (and the deluded).
The Last Word:
There is no finer or more dangerous message to humankind than to call for repentance from sins.