Your argument falls short, because he could have been injured playing the 5-10 minutes he got, and everything would be the same.Imagine the different opinions if he did get injured if he played more. We would never know if he would've made it through unscathed if he played for longer. Wasn't it gut wrenching seeing Kompany come back and then disappear again after a few minutes. City may have benefitted from him being on the pitch for longer. For Pep, if anything bad happened, it would've been a damned if he did play him and damned if he didn't play him situation. You can never please everyone. Haha.
Personally, I think it's stupid to have a player on the bench who you don't think can play 15 minutes.