Nikolas Cruz -- the Marjory Stoneman Douglas High mass shooter -- doesn't deserve a second chance ... according to his victims' families, who want him sentenced to death.
The fathers of 2 of Nikolas' 17 victims tell TMZ ... they're not buying the courtroom apology Cruz offered Wednesday, and they say he shouldn't get another shot as his trial looms.
Max Schachter, the father of 14-year-old victim Alex, says straight-up ... Cruz "is a sadistic murderer and he deserves to die." Max also says his plea for a second chance is "laughable" and believes he should get the death penalty.
Tony Montalto, whose 14-year-old daughter Gina was among those gunned down, doesn't accept Cruz's apology either, saying ... "If he wanted to do something for our families, he would've not killed our loved ones."
The way Tony sees it ... Cruz didn't give his daughter a chance when he shot her 4 times, so why should he get a second chance at life???
As we reported ... Nikolas changed his plea to guilty Wednesday and told the families of his victims he was sorry and he loved them, while begging for a second chance and making it clear he doesn't want a death sentence.
Tony, who was in court to listen to Cruz, says the mea culpa was "ridiculous" and "painful" ... and he wants Cruz prosecuted to the fullest extent of the law as a way to deter future mass shootings.
Cruz is facing life in prison or the death penalty after pleading guilty to 34 counts -- 17 premeditated murder and 17 attempted murder -- and while he thinks it should be up to the families to decide his fate ... it sounds like Cruz might not like their answer.