Ah, the wonders of Karaoke. Some people are terrible, others are average and very few are good. And yet it doesn't stop them singing, whatever their categorisation. I'm not sure which category I'm in (hopefully not the terrible one) but I do enjoy singing. I did my first public Karaoke a few days back and I enjoyed it. With a captive audience (they had to finish their beers), I tried my best to capture The Pixies, Nirvana, The Doors and The Eagles. I'm not sure whether I succeeded but I enjoyed it - I even got a fist bump for my efforts.
People in my group were (and still are) hesitant about singing in public - they hate it. I enjoy it. Maybe it's the fear of being ridiculed that compels them to keep their singing voices under lock and key. For me that's a reason to challenge the world to critique. I thrive on criticism - maybe because I'm a masochist, but the only way to improve is to be told your weaknesses. I do care if I subject others to my caterwauling but I do love singing; imagining me in the bands that I love and bringing something different to the original performance, whether intended or not.
I would recommend that everyone pushes their boundaries and hopefully discovers some new talents (or must-try-harder areas). To hell with anyone's opinion; just get up and live.