First off the is movie is a classic from the 80s and a representation of that era. This is when movies had heart, weren't afraid to make jokes because someone might get offended, and poke fun at all types of people, personalities, races, social backgrounds, etc.
Most people love this movie and consider it a classic. If you were born in the last 20 -25 years, you might be offended and your feelings might get hurt. This is however not because the movie is bad, it's because you were raised to literally be offended by anything and anyone.
This all being said, opinions on movies are subjective and everyone is entitled to their opinion, even if it's wrong.