He/she may be one of those players who /mutes everyone before the match and just doesn't talk. Looking at the match, I wouldn't consider it reportable. There's no sign of giving up in their build, or the locations of their deaths, and you said that they didn't talk, so they didn't start with the "gg ff@20" at 2 minutes in. And there's no indication of any intentional feeding. They are clearly not just trying to die, or running it down a lane, or building troll items. It sounds like he/she just didn't know how to use the ult properly and didn't do it. Which, given that it's not a damage-dealer, isn't quite the same as not using a Miss Fortune ult (for example).
Is it a bit unskilled, sure. Did it lead to missed opportunities for initiations/saves, definitely. Does it mean they were not trying to win, no.