Board Thread:General Discussion/@comment-26826023-20160201071856/@comment-27620479-20160405121233

Sloth is not lazyness, as I have stated it earlier. It is not doing everything in your abilities and power to the level that allows the presence of evil in some form. It is a cardinal sin because of it's otherwise avoidable, dire consequences. It doesn't matter if it originates from lazyness, or from being a pushover that even other monsters realize about Asgore.

No matter how hard working and kind Asgore is, he made a decision that caused suffering to him, his wife, monsters in general, and seven human presumably child. I don't say he didn't try, but Toriel can point out an available supposedly better solution. That is, Asgore performed under his abilities, and evil was born out of it, which is the definition of sloth as I know it.