I have told you guys over and over and over again: Valentine is the most incompetent villain I have EVER seen! Seriously, he just plain sucks, okay? First of all, he is supposed to be super intimidating and scary. And to be frank, I am in no way impressed. To me, this is similar to a huge man beating up on a small defenseless woman.
First off, it makes the man a complete and utter douchenozzle, but also a downright coward. Valentine is supposed to be this bad ass supposedly superior Shadowhunter but he has to get demons and use silver powder to do his dirty work. Not only that, the only time we see him directly attack someone and it’s two relatively new Downworlders.
Then let me add this: I’m pretty sure the Inquisitor would have done the same thing to Simon and Maia if she had the chance. I honestly don’t see any difference between the Clave and Valentine and Clare has yet to prove me wrong.