They came in droves and were baptized. Some of the people who came seemed to be coming for the wrong reasons. They weren't repenting. They just wanted to get baptized. Actually, we still see that today.
Baptism is a good and beautiful thing.
With baptism we become a full member of the church. But often times these are people who have no intention of turning their lives to God, and so baptism doesn't make any sense. Usually we suggest they start coming to church, so that the promises they make are real promises. This is a problem faced by just about every church, but John had it first. John, however, doesn't mince words.