The fact of the mater is, they boldly chose to release this movie 2 weeks before what will likely be the highest grossing film in film history. If this were any other situation, I'd agree that it's a bad strategy to market your film based on the actions of another, but in this case, it's entirely necessary.
When TASM is released, people will have one thought in mind, "Do I want to spend money on this movie when The Dark Knight Rises is coming out in two weeks?" Sony needs to strategically market their film in order to give people the idea that it will be worth it. By releasing their materials right after The Dark Knight Rises releases theirs, it says, "Yes, this movie is coming out next summer, but don't forget about our film either, which will be excellent as well."
And it's not always a losing strategy, especially in this case. TASM is fighting an uphill battle, they need to market around TDKR to have a prayer at Box Office success.