What do you think about me wanting to get better at photography just so I can tell other people why their shots are bad?
Why do you want to criticize other photographers?
Because I'm an asshole.
Even if you become great at photography it is still wrong to criticize other people's works. Instead of criticizing others you should help them improve.
I did so with my friend already and he thanked me for it.
Your friend thanked you because he is your friend and likely figured that you had good intentions. However, you should not try this with strangers because they will likely be offended by your criticisms.