The problem with infect is that, once you one-shot one opponent, the others tend to
gang up against you.
In addition, your deck tells your opponents what strategy you're playing since the beginning, so they will
gang up against you even sooner.
You normally want to play big creatures and grant them infect at instant speed (with
Tainted Strike, for instance), or find some way to deal direct (infect) damage when you're not supposed to.
In particular, I see you're playing
Triumph of the Hordes, which is a great infect card indeed, but works well either with big creature or a lot of them. You comply with none of these requirements, since your critters have mostly 1-2 power and 22 of them is not that much. In addition, most of your creatures already have infect, so
Triumph of the Hordes is essentially a worse
Overrun.
A commander that is known to sinergize well with infect creatures is
Saskia the Unyielding.
She allows for more color than just green and essentially gives all your creatures double strike. Moreover, you can pick the pillowfort player and still
deal damage even if you can't attack him (one recurring problem of aggro decks solved) and, once your target is dead, you could
Fling Saskia to someone's face and recast her to repeat the trick.
However, if you want to stick with your strategy, I suggest you to play more cards like
Craterhoof Behemoth and
Finale of Devastation.