When you criticize a K-pop idol and say that they're a weak singer or to put it bluntly a rather shiteous excuse for a singer hoards of delusional fangirls start bombarding you with clips of their idols singing whether it be solo stages from their concert or pre-debut clips.
The funny thing is those clips shown goes on to prove my point that they can't sing.
Furthermore they accuse you of being an anti-fan/hater and tell you that 'Oh really I bet you can't sing better than them or even dance better than them' because apparently it's my job to sing and dance for a living...yeah right.
For e.g. Big Bang's TOP/ChoomTOP's (whatever they call him) attempt at singing in 'Oh Mom' makes me want to jump off a cliff, it's great that he's trying something new and putting emotion into his singing however if singing isn't your forte then why embarrass yourself by taking such a risk? You're a 'rapper' so why not work on your rapping skills instead since it isn't really that phenomenal as people make it to be. However if you say that to VIP's or TOP stans and they would ALL show you the same clip of TOP singing 'No diggity' back in 08. Yes 08.
Oh and I forgot to mention why does G-Dragon sing anyway? He's the designated rapper of Big Bang along with TOP, can't he just stick to rapping? So when in BB's 'Cafe' (I do like this song very much btw VIP's) the song is somewhat ruined when GD starts to sing in his falsetto. Surprisingly Seungri (who's known for being the less talented vocalist) does an excellent job but he gets no credit whatsoever because GD stans are too busy fawning over how oppar's voice sounds heavenly and makes them jizz in their panties. Sure.
Ah, last but not the least Wonder Girl's Sohee. This girl can't sing. Point blank. Tell that to Wonderfuls and they shove clips of WG's 'Irony' down your throat where Sohee gets like 4 lines that barely prove anything at all plus the way she sings it sounds very unnatural...like she's in a rush to go to the loo.
I only used these examples since these peeps are the ones that I could recall off the top of my head. There are a lot worse ones out there.