Snider has never developed into anything and it is pretty obvious the Jays realized this.
Lincoln was a solid young arm, who had started and relieved in the majors. It was clearly a value-for-value trade based on the needs of each team. The Jays took a risk (imagine if Snider became good) and the Pirates took a risk (imagine if Lincoln became good).
And you can complain all you want, but Happ has developed into a very good starting pitcher. Where and how he did it is largely irrelevant. He's a Jay now and the organization clearly saw something (twice) to warrant trading for/signing him.
Argue all you want, but you can't cite a real example of an AA trade doing long-term harm to the organization.