Am I The Asshole For Picking Up A 3rd QB In My Fantasy League To Block My Opponent From Starting Him This Week?

Quick story. I'm in a fantasy league with buddies from high school, it's our 13th year doing it. Just guys doing fantasy. 2 QB league and my opponent has Kirk Cousins and Justin Herbert, who is questionable with his rib injury. He plays in the late slate of games. The only other QB on his bench is former NVP Mitch Trubisky, who played Thursday. 

So I got curious and looked at the QBs available to pick up. The top projected QB is Geno Smith, who plays in the late slate of games when we'll know for sure if Herbert will play or not. I picked him up so my opponent couldn't get him then plug him in. He'll sit on my bench and I'll release him Tuesday. The only other options he has is to pick up a Mac Jones or Davis Mills that he has to start at 1 without knowing Herbert's status, ride the Cooper Rush Express on Monday night, or roll the dice with Herbert and see if he plays. It feels wrong but damnit I think it's the right move. I think this is called playing defense. Playing to win. Obviously all of this is a moot point if Herbert plays today. 

Now many people are saying this is how you get "Tommy Pham'd" and start a fight in your league that results in Steven Cheah becoming your commissioner. But I don't care. I need a win. 

So am I the asshole for picking up Geno just so my opponent can't? Is it bad form or juju to play defense like this? 

PS. For the people who say "No one cares about your fantasy team" you're wrong. I care. I care about everyone's fantasy team. I love seeing the different rosters and match ups.