There's an important difference between criticizing a tradition, and criticizing individuals. The tradition, in this case, was greatly magnified by the parties who have a vested interest in people spending a lot of money on rings. That aspect of it conveys little benefit to the people who partake in it, or, as others have already noted, is even negative by encouraging people to spend too much of their income at a time in their life when they really ought to be focused on saving and making efficient use of their funds.

Rituals are good. A gift exchange can be great. A visible symbol is important to some people (I wear a wedding band and I like it). But the current tradition encourages something financially foolish for most modern couples.