Why do you care how much money other people spend on their weddings? Why do you care what other people spend their money on period?
Different people have different preferences. Some things I pay for would seem extravagant or unnecessary to others ($2.5K/month for a one bedroom apartment in the city). At the same time, I wouldn't pay a cent for some things that most would consider to be necessities (cable TV, cars). Does this mean that other people are spending irresponsibly? Or that I am spending irresponsibly? No. It just means that we all have our own preferences.
Some people want to have fancy weddings. Some people want to get married in a country chapel and have a cash bar at the reception. Who cares? The great thing about the modern world is that we all get to do what we want.