Similar doesn't mean it needs to have every feature of something it's not. There also isn't a crafting system that is basically the foundation of every MMO economy. The reasons to leave the trading out of a game like this far outweigh the reasons why there should be.

It's restrictive on the community.

The community is restrictive on their vision of how they want to build their game? Look, I'm on record here saying I wouldn't be against and would somewhat prefer a trading system that excluded Legendary and Exotic items. Then both sides get what they want - there is trade and you have to earn your end game gear... However, I am wholly opposed to people acting like they are entitled to anything and everything. Push comes to shove, nobody forces you to buy any game. Developers make decisions like this with thought behind them, rest assured, and no matter what they are going to upset somebody.

They could've easily implemented it, but they decided not to because then people can be lazy and give people glimmer for their gear. Bungie doesn't want that.

I don't see how it's lazy its either get lucky, not "hard work".