I want to express the concept of a crowd of people with wrong idea of good and bad things (like people from some classical books who make principal characters abandon their love and so on). Can I use the expression perverse crowd or deviant crowd. I feel that something is wrong, because these words are usually used to refer to something sexually abnormal? What is a right adjective to use?
Go ahead and use perverse. OED:
1.a. Of a person, action, etc.: going or disposed to go against what is reasonable, logical, expected, or required; contrary, fickle, irrational.
. . .
3. Obstinate, stubborn, or persistent in what is unreasonable, foolish, or wrong; remaining set in a course of action in spite of the consequences.
Yes, there is also this:
5 That is (regarded as) sexually perverted.
But sexual meanings and applications of a word need not always utterly swallow up all others.
How about the word "corrupt"? But I would suggest that it is not the crowd that is corrupt, but the members of the crowd, and since all three terms ("corrupt", "perverse", and "deviant") have personal connotations to at least some degree, I would use a construction such as "the people of the crowd were corrupt / deviant / perverse".