Shabbas! Both the points are correct.
Yes, the person has the right to get offended.
But, Gaali to Pratik ke liye hai. Uski ma ke liye nahi.
Gaaliyo ka ek hi motive hota hai. samne wale ko insult karna.
Maa-Behen wali galio ka intention kisiki maa ya behen ko gaali dena nahi hota
[for the 100th time]
then why is maa or behen included in that gaali?