Art. 19 of the Indian Constitution states that
(1) All citizens shall have the right (a) to freedom of speech and
expression...
from which is follows that you may advance any argument that you want in support of an idea. The courts have never questioned this. There is a potential grey area regarding verbal acts that cause the use of violence, but in terms of presenting reasons that such-and-such acts are good (or bad), that form of expression is absolutely protected. The grey area comes from clause 2:
Nothing in sub clause (a) of clause (1) shall affect the operation
of any existing law, or prevent the State from making any law, in so
far as such law imposes reasonable restrictions on the exercise of the
right conferred by the said sub clause in the interests of the
sovereignty and integrity of India, the security of the State,
friendly relations with foreign States, public order, decency or
morality or in relation to contempt of court, defamation or incitement
to an offence
whereby a law against inciting to violence might pass constitutional muster. "Justification" of an action is very different from "inciting" to do an act.
