Steve Harwell and C-Knight's omissions from the Grammys' "In Memoriam" segment Sunday was rude and disrespectful ... according to their nearest and dearest.
Robert Hayes, a rep for Smash Mouth's late lead singer, is hurt over the snub ... though he tells TMZ it didn't surprise him because the Recording Academy never acknowledged Steve when he was alive ... so why would they honor him when he passed?
Smash Mouth was nominated for a Grammy once, in 2000, but didn't win.
His remarks were cutting ... asking who even bothered to watch the Grammys anymore -- and expressing his belief the award ceremony hadn't been good in more than 20 years.
Steve left a lasting influence in the music industry before he passed away in Sept 2023 ... and only 2 months later, fellow artist C-Knight also died, having been taken off life support following complications from diabetes.
C-Knight's brother George Lee Blount echoed similar feelings of hurt and outrage over the "In Memoriam" exclusion.
George tells TMZ ... while C-Knight and his band The Dove Shack never scooped a Grammy, their impact on G-funk and hip hop is undeniable -- adding he was a hip hop legend, and the least they could've done was give him a mention.
George is hoping the same mistake doesn't happen again, urging the Grammys to do more research into artists to understand the hard work and sacrifice they put into their music careers.
For a fair system, he urges Grammys to be more like the BET Awards ... noting they have a better understanding of Black artists and, therefore, can appropriately award artists who've made an impact in music.