"WTF was all this about?"
That's former boxing superstar Ricky Hatton UNLEASHING on his former opponent Floyd Mayweather ... essentially saying the exhibition with Logan Paul was an INSULT to the sport he loves.
42-year-old Hatton -- The Ring magazine's 2005 Fighter of the Year -- HATED everything about Floyd vs. Logan and went off the two in a scathing IG post early Monday morning.
"My personal opinion that was s**t for boxing," Hatton said.
"What happened to the days where fighters would put there lives on the line to try be the best and at least fight the best.