You've played this since 2007? Because you're not acting like it. Why throw to first when you didn't like your pitch instead of just stepping off the mound? The baserunner is stealing because you're accidentally squeezing the trigger on the controller during the at-bat (and, yes, you are. this isn't a glitch. it's a well-known common mistake). I think you're a bit rusty. Also, maybe play a few more games.