I honestly don't watch that much Korean TV even though I live in Korea, but this weekend I was in a hotel and SMTM was the only thing on.
My friend and I were watching it (we're both American) and it was just really, really cringey. We couldn't take it seriously at all (and we both like quite a bit of Korean hip hop)
I have also heard complaints from a lot of Korean underground rappers that the hosts of SMTM pretty much set the style for hip hop in Korea. Like, if they say one way of rapping is awesome, most regular listeners will think so too, if they say another trait is bad, people will probably agree. Since the hosts are successful, people trust their judgement and taste level and their opinions are formed wholly by the show. Its basically monopolizing the genre I guess.
I think there are a lot of hip hop artists in Korea that are doing amazing things, but the structure and feel of SMTM just made it seem like a joke. Like people are auditioning to be a rapper almost as if they were auditioning for a role in a movie. They want to play the role but they really aren't that person.