Yes there is a subjective interpretation, what maybe vulgar for you may not be vulgar for others and vice versa. But vulgarity is not something that is 100% subjective. Society draws an objective line. These lines prohibit vulgar behavior in public, it tries to prevent vulgar content in cinema. In the case with pelvic thrusting and other dance movements by Salman and Govinda, I think you are completely and utterly ignoring objective definitions of vulgarity as defined by society at large.
Vulgar by one of the dictionary definitions is "Making explicit and offensive reference to sex or bodily functions; coarse and rude"
Pelvic thrusting is a sexual act and an explicit reference to sex.
Cock flapping is an explicit reference to one's phallus.
Rubbing crotches together is a sexual act and an explicit reference to sex.
By definition those dance forms are vulgar. Now despite being vulgar, I will give you that it has become societally and culturally acceptable in Indian cinema. But there is no way you can claim it is not vulgar without dismissing the most objective definitions of vulgarity.
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