Paul evidently felt these qualities marked the false teachers especially. Therefore he charged Titus to rebuke them sharply. [source][source][source]
"Failure to confront problems within the church, whether theologically or practically based, may be indicative of a basic indifference with regard to God"s truth or the nurturing of truly Christian relationships. The fear of giving offense and a highly individualized view of personal faith may discourage church leaders from following the biblical mandate to rebuke. The restoration that is possible both in fellowship and in sound doctrine is compromised by this reluctance to confront. Loving, sensitive, yet firm confrontation can result in stronger relationships and restored unity or perhaps a needed purging of those who deny the truth." [1][source]
Apparently Jewish myths and laws laid down by those who rejected God"s truth fascinated these false teachers (cf. Matthew 15:9; Mark 7:7; 1 Timothy 1:4; 1 Timothy 4:3-7; 1 Timothy 6:3-4; 2 Timothy 4:4; Colossians 2:21-22). [source][source][source]
The context does not clarify whether those who turn away from the truth are believers or unbelievers (cf. 2 Thessalonians 2:3). They could be Christians (cf. Luke 8:13; 1 Timothy 4:1; Hebrews 3:12) [2] or non-Christians (cf. Luke 13:27; 2 Thessalonians 2:11) or both. [source][source][source]