I think people are just saying that from the human side of the game - this late move sucks for Tepera. I don't think any reasonable person is suggesting they shouldn't have added Morales because it hurts Tepera's feelings....but for a fringe major leaguer - to be told you made the team (probably after months of hard work) must have felt pretty good (he likely has the attitude that if you give me a chance - I'll run with it) - only to be let down right before opening day. I'm sure he realises it's business and that he'll pitch for the Jays this year.
I'm also sure the Jays would have preferred to avoid this timing for all the reasons noted above...but it didn't happen. They sit down, have a man to man talk about the situation, reassure him he'll be part of the team this year and move on.