All linesmen have to make these decisions in real time and often do well, hence why clangers like this are worthy of discussion. It's a really poor call man, no excuse for it.
Horrible is a bit much like Judging offsides is a very tough job
Aye when there's a couple of inches in it, what's the point in having linesmen if catching a player half a yard offside is hard? May as well scrap them.