They incorporated the most elaborate cheating scheme ever.
You do know that pitchers ability to make money at the MLB level primarily has to do with can they get guys out. So stealing signs to know what pitch is coming is hurting their ability to earn future money.
Imagine how pitchers who faced the cheaters feel about them. Some guy who just was brought up to the majors and is hoping to stick with the club if he pitches well. Then gets touched up for a bunch of hits and runs by the astros and finds out they knew what pitch he has throwing. No wonder a lot of the cheating players were thrown at.