Words being offensive doesnt mean everyone will be offended by them, some will and some wont wether that be the word cunt or paki, I agree with you on that.
So when you say those sort of words you risk offending someone, wether you care about the risk of offending someone or not is of course your choice, in some people's case they deliberately use the paki purely to cause offence, in other cases people dont realise the implications of it as a word, so some people intentionally make that choice and others dont.

With regards to the difference between the word scot and paki, as per dozens of replies in this thread, its because of how the work paki has been used that it now has conatations, much like the word cunt, were you not paying attention to the disucssion you were in?
If you havent understood it by now, you probably just arent capable of understanding it TBH as multiple people in this thread have given good explanations as to how the english language evolves with regards words taking on meanings based on how they are commonly used etc.