Ex-NFL Running back Thomas Jones is BLASTING Giants stud Jason Pierre-Paul ... saying JPP is a total BUFFOON for mangling his hand in a fireworks accident on the 4th of July.
Jones -- who spent 12 seasons in the league -- was commenting on the recent report that JPP had a finger amputated due to the severity of the fireworks injury ... and wrote bluntly:
"NOW THIS IS A MORON!!"
"These guys running around looking like Raptors with 3 and 4 fingers and s**t tryna light firecrackers at home. What the hell is goin on!!!"
He wasn't done ... Jones continued with another brutally honest message:
"Attention All NFL Players: LEAVE THE F*****G FIREWORKS ALONE!! YOU BUFOONS!!!!"
Dude's gotta point.