The Caitlin Clark effect hate is real ... so says Nancy Lieberman, who tells TMZ Sports players need to embrace the "cash cow" and stop being petty.
We spoke with Lieberman after the All-Star voting results were released ... which showed Clark as the 9th-ranked WNBA guard in the player vote.
Lieberman -- a WNBA Hall of Famer who played in the 1990s -- was shocked by the low vote count and believes it's all driven by jealousy .