Magic the gathering clarification?

Ok so i was playing a magic game with my friends and one of them use the card "Perish" a href="http://gatherer.wizards.com/Pages/Card/Details.aspx?multiverseid=14581" rel="nofollow"http://gatherer.wizards.com/Pages/Card/D…/a (it destroys all green creatures and they can not be regenerated) i already had out the card "Steely Resolve" a href="http://gatherer.wizards.com/Pages/Card/Details.aspx?multiverseid=40130" rel="nofollow"http://gatherer.wizards.com/Pages/Card/D…/a (This card make the chosen monster type {in this case elf, my entire deck is made of elves} not be able to be the target of of spells or abilities.) So my friend says that because his card destroys all green monsters that it does not say it targets my monsters and therefor my monsters (all elves) have to be destroyed. i disagree with his point because his card changes my monsters and that would be targeting in my opinion weather good or bad. do u agree with me? or him? also if you know which one for sure it right then that would be a HUGE help in the future when i play.