Basically, you work with what you have.

Would you mock the guy at church who isn't wearing a $500 dollar suit.

If someone can afford to shell out thousands of dollars for a complete outfit great for them. But to belittle someone who cannot is not a good thing.

The real intent of formal wear is for the person to show that they respect and appreciate the event enough to put on their best. Whether that best is bought new from a retail store or second hand from a thrift shop, the person has made the effort to wear their best and most appropriate clothing for the event.