If someone is really shy or quiet they are easy to get picked on by others. So if someone or a bunch of people who belittes you constantly for their own sense of humour amongst their friends, or excludes you a lot, and therefore you end up saying all these things out of your own build up of frustration and anger through your whole life about them, and talking bad words behind their backs, does Allah still blame the victim for this especially if they have been picked on their entire life?
ليس المؤمن بالطعان ولا باللعان
It means that we as believers should not say bad words or harm others by offending or damming them. However, Allah says "والذين اذا أصابهم البغي هم ينتصرون" which gives a description to believers that if someone humiliates them or attacks them they give a defense and even punish the attackers. It is not about revenge but about being strong and preciously defend his religion.
People who offend you are only temporary , try to find good friends and company . If they really harm you and offend you do not be shy to escalate that to the manager or your parents (etc.). You do NOT have to live with it. They are wrong and they must change by all laws.